Led tube lamp

ABSTRACT

A circuit board configuration adapted to carry electronic components of a power supply module is provided. The circuit board configuration comprises: a first circuit board, having a first plane configured to dispose and connect a part of the electronic components; and a second circuit board, electrically connected to the first circuit board and having a second plane configured to dispose and connect another part of the electronic components, wherein at least one of the first and the second circuit boards is disposed, perpendicular to an axial direction of the lamp tube, in an interior space formed by the lamp tube and at least one of the two end caps, so that the a direction normal to the first and the second planes is substantially parallel to the axial direction of the lamp tube.

RELATED APPLICATIONS

This application is a Continuation application of U.S. patentapplication Ser. No. 16/667,370, filed on Oct. 29, 2019, which is aContinuation-In-Part application of U.S. patent application Ser. No.16/436,454, filed on Jun. 10, 2019, which is a Continuation applicationof U.S. patent application Ser. No. 16/143,755, filed on Sep. 27, 2018,which is a Continuation-In-Part application of U.S. patent applicationSer. No. 16/106,060, filed on Aug. 21, 2018, which is a Continuationapplication of U.S. patent application Ser. No. 15/662,094, filed onJul. 27, 2017, which is a Continuation-In-Part application of U.S.patent application Ser. No. 15/626,238, filed on Jun. 19, 2017, which isa Continuation application of U.S. patent application Ser. No.15/373,388, filed on Dec. 8, 2016, which is a Continuation-In-Partapplication of U.S. patent application Ser. No. 15/339,221, filed onOct. 31, 2016, U.S. patent application Ser. No. 15/211,813, filed onJul. 15, 2016, U.S. patent application Ser. No. 15/084,483, filed onMar. 30, 2016, and U.S. patent application Ser. No. 15/065,892, filed onMar. 10, 2016, the disclosure of each of which is incorporated in itsentirety by reference herein. U.S. patent application Ser. No.15/339,221 is also a Continuation-In-Part application of U.S. patentapplication Ser. No. 15/210,989, filed on Jul. 15, 2016, which is aContinuation-In-Part application of U.S. patent application Ser. No.15/066,645, filed on Mar. 10, 2016, which is a Continuation-In-Partapplication of U.S. patent application Ser. No. 14/865,387, filed onSep. 25, 2015, the disclosure of each of which is incorporated in itsentirety by reference herein. U.S. patent application Ser. No.15/210,989, filed on Jul. 15, 2016 is also a Continuation-In-Partapplication of U.S. patent application Ser. No. 15/205,011, filed onJul. 8, 2016, which is a Continuation-In-Part application of U.S. patentapplication Ser. No. 15/150,458, filed on May 10, 2016, which is aContinuation-In-Part 14/865,387, filed on Sep. 25, 2015, the disclosureof each of which is incorporated in its entirely by reference herein.U.S. patent application Ser. No. 15/211,813 is also aContinuation-In-Part application of U.S. patent application Ser. No.15/150,458, filed on May 10, 2016, which is a Continuation-In-Partapplication of U.S. patent application Ser. No. 14/865,387, filed onSep. 25, 2015. U.S. patent application Ser. No. 15/084,483, filed onMar. 30, 2016, is also a Continuation-In-Part application of U.S. patentapplication Ser. No. 14/865,387, filed on Sep. 25, 2015. U.S. patentapplication Ser. No. 15/065,892, filed on Mar. 10, 2016, is also aContinuation-In-Part application of U.S. patent application Ser. No.14/865,387, filed on Sep. 25, 2015. U.S. patent application Ser. No.14/865,387, filed on Sep. 25, 2015 claims priority under 35 U.S.C.119(e) to Chinese Patent Applications No.: CN 201410507660.9 filed on2014 Sep. 28; CN 201410508899.8 filed on 2014 Sep. 28; CN 201510104823.3filed on 2015 Mar. 10; CN 201510134586.5 filed on 2015 Mar. 26; CN201510133689.x filed on 2015 Mar. 25; CN 201510155807.7 filed on 2015Apr. 3; CN 201510193980.6 filed on 2015 Apr. 22; CN 201510284720.x filedon 2015 May 29; CN 201510338027.6 filed on 2015 Jun. 17; CN201510373492.3 filed on 2015 Jun. 26; CN 201510364735.7 filed on 2015Jun. 26; CN 201510378322.4 filed on 2015 Jun. 29; CN 201510406595.5filed on 2015 Jul. 10; CN 201510486115.0 filed on 2015 Aug. 8; CN201510428680.1 filed on 2015 Jul. 20; CN 201510557717.0 filed on 2015Sep. 6; CN 201510595173.7 filed on 2015 Sep. 18, the disclosures of eachof which are incorporated herein in their entirety by reference.

In addition, U.S. patent application Ser. No. 15/066,645, from whichU.S. patent application Ser. No. 15/210,989 claims priority as aContinuation-In-Part also claims priority under 35 U.S.C. 119(e) toChinese Patent Applications Nos.: CN 201510530110.3 filed on 2015 Aug.26; CN 201510499512.1 filed on 2015 Aug. 14; CN 201510448220.5 filed on2015 Jul. 27; and CN 201510645134.3 filed on 2015 Oct. 8, thedisclosures of each of which are incorporated herein in their entiretyby reference.

In addition, U.S. patent application Ser. No. 15/205,011, from whichU.S. patent application Ser. No. 15/210,989 claims priority as aContinuation-in-Part also claims priority under 35 U.S.C. 119(e) toChinese Patent Application Nos.: CN 201610327806.0, filed on May 18,2016; and CN 201610420790.8, filed on Jun. 14, 2016, the disclosures ofeach of which are incorporated herein in their entirety by reference.

In addition, U.S. patent application Ser. No. 15/210,989 also claimspriority under 35 U.S.C. 119(e) to Chinese Patent Application Nos.: CN201510848766.X, filed on Nov. 27, 2015; CN 201510903680.2, filed on Dec.9, 2015; CN 201610132513.7, filed on Mar. 9, 2016; CN 201610142140.1,filed on Mar. 14, 2016; and CN 201610452437.8, filed on Jun. 20, 2016,the disclosures of each of which are incorporated herein in theirentirety by reference. In addition, U.S. patent application Ser. No.15/210,989 also claims priority under 35 U.S.C. 119(e) to Chinese PatentApplication Nos.: CN 201510530110.3, filed on Aug. 26, 2015; CN201510499512.1, filed on Aug. 14, 2015; CN 201510617370.4, filed on Sep.25, 2015; CN 201510645134.3, filed on Oct. 8, 2015; CN 201510726365.7,filed on Oct. 30, 2015; CN 201610044148.4, filed on Jan. 22, 2016; CN201610051691.7, filed on Jan. 26, 2016; CN 201610085895.2, filed on Feb.15, 2016; CN 201610087627.4, filed on Feb. 16, 2016; CN 201610281812.7,filed on Apr. 29, 2016; CN 201510705222.8, filed on Oct. 27, 2015; CN201610050944.9, filed on Jan. 26, 2016; CN 201610098424.5, filed on Feb.23, 2016; and CN 201610120993.5, filed on Mar. 3, 2016, the disclosuresof each of which are incorporated herein by reference in their entirety.

In addition, U.S. patent application Ser. No. 15/339,221 also claimspriority under 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201610876593.7, filed on Oct. 8, 2016, the entire contents of which areincorporated herein by reference.

In addition, U.S. patent application Ser. No. 15/373,388 claims priorityunder 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201610878349.4, filed on Oct. 8, 2016; CN 201610955338.1, filed on Oct.27, 2016; CN 201610955342.8, filed on Oct. 27, 2016; CN 201610975119.X,filed on Nov. 3, 2016; CN 201611057357.9, filed on Nov. 25, 2016; CN201610177706.4, filed on Mar. 25, 2016; and CN 201610890527.5, filed onOct. 12, 2016, the disclosures of each of which are incorporated hereinby reference in their entirety.

In addition, U.S. patent application Ser. No. 15/662,094 claims priorityunder 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201710036966.4, filed on Jan. 19, 2017; CN 201710170620.3, filed on Mar.21, 2017; CN 201710158971.2, filed on Mar. 16, 2017; CN 201710258874.0,filed on Apr. 19, 2017; CN 201710295599.X, filed on Apr. 28, 2017; andCN 201710591551.3, filed on Jul. 19, 2017, the disclosures of each ofwhich are incorporated herein by reference in their entirety.

In addition, U.S. patent application Ser. No. 16/143,755 also claimspriority under 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201710888946.X, filed on Sep. 27, 2017; CN 201711298908.5, filed on Dec.8, 2017; CN 201810032366.5, filed on Jan. 12, 2018; CN 201810130074.5,filed Feb. 8, 2018; CN 201810205729.0, filed Mar. 13, 2018; CN201810272726.9, filed Mar. 29, 2018; CN 201810292824.9, filed Mar. 30,2018; CN 201810326908.X, filed Apr. 12, 2018; CN 201810752429.4, filedJul. 10, 2018; CN 201811005720.1, filed Aug. 30, 2018; and CN201811053085.4, filed Sep. 10, 2018, the disclosures of each of whichare incorporated herein by reference in their entirety.

In addition, this Application claims priority under 35 U.S.C. 119(e) toChinese Patent Application No.: CN 201811277947.1, filed on Oct. 30,2018; CN 201811441563.9, filed on Nov. 29, 2018; CN 201910412116.9,filed on May 17, 2019; CN 201910537220.0, filed Jun. 20, 2019; and CN201910732298.8, filed Aug. 9, 2019, the disclosures of each of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The disclosed embodiments relate to the features of light emitting diode(LED) lighting. More particularly, the disclosed embodiments describevarious improvements for LED tube lamps.

BACKGROUND

LED lighting technology is rapidly developing to replace traditionalincandescent and fluorescent lighting. LED tube lamps are mercury-freein comparison with fluorescent tube lamps that need to be filled withinert gas and mercury. Thus, it is not surprising that LED tube lampsare becoming a highly desired illumination option among differentavailable lighting systems used in homes and workplaces, which used tobe dominated by traditional lighting options such as compact fluorescentlight bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tubelamps include improved durability and longevity and far less energyconsumption. Therefore, when taking into account all factors, they wouldtypically be considered as a cost effective lighting option.

Typical LED tube lamps have a lamp tube, a circuit board disposed insidethe lamp tube with light sources being mounted on the circuit board, andend caps accompanying a power supply provided at two ends of the lamptube with the electricity from the power supply transmitting to thelight sources through the circuit board. However, existing LED tubelamps have certain drawbacks. For example, the typical circuit board isrigid and allows the entire lamp tube to maintain a straight tubeconfiguration when the lamp tube is partially ruptured or broken, andthis gives the user a false impression that the LED tube lamp remainsusable and is likely to cause the user to be electrically shocked uponhandling or installation of the LED tube lamp.

Conventional circuit design of LED tube lamps typically doesn't providesuitable solutions for complying with relevant certification standards.For example, since there are usually no electronic components in afluorescent lamp, it's fairly easy for a fluorescent lamp to becertified under EMI (electromagnetic interference) standards and safetystandards for lighting equipment as provided by UnderwritersLaboratories (UL). However, there are a considerable number ofelectronic components in an LED tube lamp, and therefore considerationof the impacts caused by the layout (structure) of the electroniccomponents is important, resulting in difficulties in complying withsuch standards.

Further, the driving of an LED uses a DC driving signal, but the drivingsignal for a fluorescent lamp is a low-frequency, low-voltage AC signalas provided by an AC power line, a high-frequency, high-voltage ACsignal provided by a ballast, or even a DC signal provided by a batteryfor emergency lighting applications. Since the voltages and frequencyspectrums of these types of signals differ significantly, simplyperforming a rectification to produce the required DC driving signal inan LED tube lamp may not achieve the LED tube lamp's compatibility withtraditional driving systems of a fluorescent lamp.

Currently, LED tube lamps used to replace traditional fluorescentlighting devices can be primarily categorized into several types. One isfor ballast-compatible LED tube lamps, e.g., direct replacement T-LEDlamp, which directly replaces fluorescent tube lamps without changingany circuit on the lighting device; and another one is for ballastby-pass LED tube lamps, which omit traditional ballast on their circuitand directly connect the commercial electricity to the LED tube lamp incertain installation configuration. The latter LED tube lamp is suitablefor the new surroundings in fixtures with new driving circuits and LEDtube lamps. The ballast-compatible LED tube lamp is also known as“Type-A” LED tube lamp, and the ballast by-pass LED tube lamp providedwith a lamp driving circuit is also known as a “Type-B” LED tube lamp.In the prior art, there is also a mix type LED tube lamp which known as“Type-A+B” LED tube lamp. Type-A+B LED tube lamp can be consideredeither a Type-A LED tube lamp or a Type-B LED tube lamp since it can beoperated in both installation configuration. In other words, if theType-A+B LED tube lamp is installed into a lamp socket with a ballast,the Type-A+B LED tube lamp operates as a Type-A LED tube lamp; and ifthe Type-A+B LED tube lamp is installed into a lamp socket directlyconnected to the commercial electricity, the Type-A+B tube lamp operatesas a Type-B LED tube lamp.

In the prior art, when a Type-B LED tube lamp has an architecture withdual-end power supply and one end cap thereof is inserted into a lampsocket but the other is not, since the lamp socket corresponding to theType-B LED tube lamp is configured to directly receive the commercialelectricity without passing through a ballast, an electric shocksituation could take place for the user touching the metal or conductivepart of the end cap which has not been inserted into the lamp socket. Inaddition, due to the frequency of the voltage provided from the ballastbeing much higher than the voltage directly provided from the commercialelectricity/AC mains, the skin effect occurs when the leakage current isgenerated in the Type-B LED tube lamp, and thus the human body would notbe harmed by the leakage current.

Therefore, since the Type-B LED tube lamp has higher risk of electricshock/hazard, compared to the Type-A, the Type B-LED tube lamp isrequested to have extremely low leakage current for meeting the strictrequirements in the safety certification standard (e.g., UL, CE, GS).

Due to the above technical issues, even many well-known internationalluminaries and LED lamps manufacturers also strand at the bottleneck ondevelopment of the ballast by-pass/Type-B LED tuba lamps having dual-endpower supply structure. Taking GE lighting corporation for the example,according to the marketing material titled “Considering LED tubes”published on Jul. 8, 2014, and the marketing material titled“Dollars&Sense: Type-B LED Tubes” published on Oct. 21, 2016, GElighting corporation asserts, over and over again, that the drawback ofthe risk of electric shock that occurs in the Type-B LED tube lampcannot be overcome, and thus GE lighting corporation would not performfurther product commercialization and sales consideration.

In the prior art, a solution of disposing a mechanical structure on theend cap for preventing electric shock is proposed. In this electricshock protection design, the connection between the external power andthe internal circuit of the tube lamp can be cut off or established bythe mechanical component's interaction/shifting when a user installs thetube lamp, so as to achieve the electric shock protection.

SUMMARY

It's specially noted that the present disclosure may actually includeone or more inventions claimed currently or not yet claimed, and foravoiding confusion due to unnecessarily distinguishing between thosepossible inventions at the stage of preparing the specification, thepossible plurality of inventions herein may be collectively referred toas “the (present) invention” herein.

Various embodiments are summarized in this section, and may be describedwith respect to the “present invention,” which terminology is used todescribe certain presently disclosed embodiments, whether claimed ornot, and is not necessarily an exhaustive description of all possibleembodiments, but rather is merely a summary of certain embodiments.Certain of the embodiments described below as various aspects of the“present invention” can be combined in different manners to form an LEDtube lamp or a portion thereof.

The present disclosure provides a novel LED tube lamp, and aspectsthereof.

According to some embodiments, a power supply module is configured toprovide, based on an external driving signal, a driving current fordriving an LED tube lamp. The power supply module includes a detectionpath circuit, configured to establish a detection path which is capableof affecting an electrical signal on a power line of the power supplymodule when the detection path is turned on, and a driving circuit,electrically connected to the detection path circuit, and configured toproduce the driving current based on the external driving signal. Whenthe driving circuit is activated by receiving the external drivingsignal, the driving circuit enters into a first mode to detect whether aforeign external impedance is electrically connected to the LED tubelamp. When the foreign external impedance is detected, the drivingcircuit remains in the first mode, and when the foreign externalimpedance is not detected, the driving circuit enters into a second modeto produce the driving current. The driving circuit is furtherconfigured to obtain a dimming message from the electrical signal andadjust the magnitude of the driving current according to the dimmingmessage when in the second mode.

According to some embodiments, a method for determining whether aforeign external impedance is electrically connected to an LED tube lampis provided. The method includes follow steps: sampling a voltage on adetection path disposed in the LED tube lamp at a first point in time toobtain a first voltage level; issuing, after the first point in time, apulse signal to temporarily turn on the detection path; sampling thevoltage on the detection path at a second point in time to obtain asecond voltage level, wherein the second point in time is within theperiod of the detection path being turned on; and generating anindication for indicating whether the foreign external impedance iselectrically connected to the LED tube lamp according to the firstvoltage level and the second voltage level.

According to some embodiments, an LED tube lamp including a lamp tube,two end caps, an LED light strip, a plurality of LED chips, and a powersupply module is provided. The end caps are connected to respective endsof the lamp tube. The LED light strip is mounted on the inner surface ofthe lamp tube. The LED chips are disposed on the LED light strip. Thepower supply module is electrically connected to the LED chips via theLED light strip, and configured to drive the LED chips to emit light.The power supply module includes a detection path circuit and a drivingcircuit. The detection path circuit is configured to establish adetection path which is capable of affecting an electrical signal on apower line of the power supply module when the detection path is turnedon. The driving circuit is electrically connected to the detection pathcircuit, and configured to produce the driving current based on theexternal driving signal

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1C are plane cross-sectional views schematically illustratingan LED tube lamp including an LED light strip that is a bendable circuitsheet with ends thereof passing across the transition region of the lamptube of the LED tube lamp to be connected to a power supply according tosome exemplary embodiments;

FIG. 2 is a block diagram illustrating leads that are disposed betweentwo end caps of an LED tube lamp according to some exemplaryembodiments;

FIG. 3A is a perspective view schematically illustrating a circuit boardassembly composed of a bendable circuit sheet of an LED light strip anda printed circuit board of a power supply according to some exemplaryembodiments;

FIG. 3B is a perspective view schematically illustrating anotherarrangement of a circuit board assembly, according to some exemplaryembodiments;

FIG. 4A is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 4B is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 4C is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 5A-5C are block diagrams of exemplary power supply modules in anLED tube lamp according to some exemplary embodiments;

FIGS. 6A-6B are schematic diagrams of exemplary LED modules according tosome exemplary embodiments;

FIGS. 7A-7F are schematic circuit diagrams of exemplary rectifyingcircuits according to some exemplary embodiments;

FIGS. 8A-8E are block diagrams of exemplary filtering circuits accordingto some exemplary embodiments;

FIG. 9A is a block diagram of a driving circuit according to someexemplary embodiments;

FIGS. 9B-9E are schematic diagrams of exemplary driving circuitsaccording to some exemplary embodiments;

FIGS. 10A-10D are signal waveform diagrams of exemplary driving circuitsaccording to some exemplary embodiments;

FIGS. 11A and 11B are block diagrams of exemplary power supply modulesin an LED tube lamp according to some exemplary embodiments;

FIG. 11C is a schematic diagram of an over-voltage protection (OVP)circuit according to some exemplary embodiments;

FIG. 11D is a block diagram of an overvoltage protection circuitaccording to some embodiments;

FIG. 11E is a schematic diagram of an overvoltage protection circuitaccording to some embodiments;

FIGS. 11F-11H are schematic diagrams of a part of an overvoltageprotection circuit according to some embodiments;

FIGS. 12A and 12B are block diagrams power supply modules in an LED tubelamp according to some exemplary embodiments;

FIG. 12C is a schematic diagram of an auxiliary power module accordingto some exemplary embodiments;

FIG. 12D is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIG. 12E is a block diagram of an exemplary auxiliary power moduleaccording to some exemplary embodiments;

FIG. 12F is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIGS. 12G-12H are block diagrams of exemplary auxiliary power modulesaccording to some exemplary embodiments;

FIGS. 12I-12J are schematic structures of an auxiliary power moduledisposed in an LED tube lamp according to some exemplary embodiments;

FIGS. 12K-12M are block diagrams of exemplary LED lighting systemsaccording to some exemplary embodiments;

FIGS. 12N-12O are schematic circuit diagrams of auxiliary power modulesaccording to some exemplary embodiments;

FIGS. 12P-12Q are charge-discharge waveforms of auxiliary power modulesaccording to some exemplary embodiments;

FIGS. 13A-13C are block diagrams of exemplary LED lighting systemsaccording to some exemplary embodiments;

FIG. 14 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments;

FIG. 15A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 15B-15F are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 16A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 16B-16E are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 17A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 17B-17E are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 18A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 18B-18F are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 19A a block diagram of an installation detection module accordingto some exemplary embodiments;

FIGS. 19B-19E are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 20A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 20B-20C are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 21A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 21B-21D are schematic circuit diagrams of an installation detectionmodule according to some exemplary embodiments;

FIGS. 22A-22B are block diagrams of installation detection modulesaccording to some exemplary embodiments;

FIG. 23 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments;

FIG. 24A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 24B is a schematic circuit diagram of an installation detectionmodule according to some exemplary embodiments;

FIG. 25 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments;

FIG. 26A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 26B-26D are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIGS. 26E and 26F are signal waveform diagram of an installationdetection module according to some embodiments;

FIGS. 26G and 26H are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 26I is a schematic circuit diagram of a power supply module havingthe functions of constant-current conversion, electric-shock detection,and dimming control according to some embodiments;

FIG. 27A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 27B is a schematic circuit diagram of an installation detectionmodule according to some exemplary embodiments;

FIG. 28A is a block diagram of an installation detection module for anLED tube lamp according to some embodiments;

FIG. 28B is a schematic circuit diagram illustrating a control circuitof an installation detection module according to some embodiments;

FIG. 29A is a block diagram of an installation detection module for anLED tube lamp according to some embodiments;

FIGS. 29B and 29C are schematic circuit diagrams of a bias adjustmentcircuit according to some embodiments;

FIG. 30A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 30B is schematic diagram of a driving circuit with an electricshock detection function according some exemplary embodiments;

FIG. 31A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 31B is a schematic circuit diagram of a driving circuit with anelectric shock detection function and a detection triggering circuitthereof according to some exemplary embodiments;

FIG. 31C is an internal block diagram of an integrated controller of adriving circuit with an electric shock detection function according tosome exemplary embodiments;

FIG. 31D is a schematic circuit diagram of a driving circuit with anelectric shock detection function and a detection triggering circuitthereof according to some exemplary embodiments;

FIG. 32 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments;

FIG. 33A is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIGS. 33B and 33C are schematic circuit diagrams of an installationdetection module according to some exemplary embodiments;

FIG. 34 is a block diagram of an installation detection module accordingto some exemplary embodiments;

FIGS. 35A and 35B are a schematic circuit diagrams of bias circuits ofan installation detection module according to some exemplaryembodiments;

FIG. 36 is a block diagram of a detection pulse generating moduleaccording to some exemplary embodiments;

FIGS. 37A and 37B are schematic circuit diagrams of detection pulsegenerating modules according to some exemplary embodiments;

FIG. 38 is a circuit diagram of a ballast detection module according tosome embodiments;

FIGS. 39A-39D are schematic signal waveform diagrams of detection pulsegenerating modules according to some exemplary embodiments;

FIG. 40 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments;

FIGS. 41A-41G are schematic signal waveform diagrams of power supplymodules according to some exemplary embodiments;

FIG. 42A is a block diagram of a power supply module according to someembodiments;

FIG. 42B is a block diagram of a misuse warning module according to someembodiments;

FIG. 43 is a block diagram of a power supply module according to someembodiments;

FIG. 44A is a flowchart of a relamping detection method according tosome exemplary embodiments;

FIG. 44B is a flowchart of an emergency detection method according tosome exemplary embodiments;

FIG. 44C is a flowchart of a power off detection method according tosome exemplary embodiments;

FIG. 44D is flowchart of steps of a method to control a misuse warningmodule according to some embodiments; and

FIG. 44E is flowchart of steps of a method to control an installationdetection module according to some embodiments.

DETAILED DESCRIPTION

The present disclosure provides a novel LED tube lamp. The presentdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only. It is not intended to beexhaustive or to be limited to the precise form disclosed. These exampleembodiments are just that—examples—and many implementations andvariations are possible that do not require the details provided herein.It should also be emphasized that the disclosure provides details ofalternative examples, but such listing of alternatives is notexhaustive. Furthermore, any consistency of detail between variousexamples should not be interpreted as requiring such detail—it isimpracticable to list every possible variation for every featuredescribed herein. The language of the claims should be referenced indetermining the requirements of the invention.

In the drawings, the size and relative sizes of components may beexaggerated for clarity. Like numbers refer to like elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, or steps, these elements, components, regions, layers, and/orsteps should not be limited by these terms. Unless the context indicatesotherwise, these terms are only used to distinguish one element,component, region, layer, or step from another element, component,region, or step, for example as a naming convention. Thus, a firstelement, component, region, layer, or step discussed below in onesection of the specification could be termed a second element,component, region, layer, or step in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to or “on” another element, it can be directlyconnected or coupled to or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, there areno intervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). However, the term “contact,” as used herein refers todirect connection (i.e., touching) unless the context indicatesotherwise.

Embodiments described herein will be described referring to plane viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “equal,” “planar,” or “coplanar,” as used hereinwhen referring to orientation, layout, location, shapes, sizes, amounts,or other measures do not necessarily mean an exactly identicalorientation, layout, location, shape, size, amount, or other measure,but are intended to encompass nearly identical orientation, layout,location, shapes, sizes, amounts, or other measures within acceptablevariations that may occur, for example, due to manufacturing processes.The term “substantially” may be used herein to emphasize this meaning,unless the context or other statements indicate otherwise. For example,items described as “substantially the same,” “substantially equal,” or“substantially planar,” may be exactly the same, equal, or planar, ormay be the same, equal, or planar within acceptable variations that mayoccur, for example, due to manufacturing processes.

Terms such as “about” or “approximately” may reflect sizes,orientations, or layouts that vary only in a small relative manner,and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

Terms such as “transistor”, used herein may include, for example, afield-effect transistor (FET) of any appropriate type such as N-typemetal-oxide-semiconductor field-effect transistor (MOSFET), P-typeMOSFET, GaN FET, SiC FET, bipolar junction transistor (BJT), DarlingtonBJT, heterojunction bipolar transistor (HBT), etc.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo devices, an electrically insulative underfill or mold layer, etc.)is not electrically connected to that component. Moreover, items thatare “directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, etc. As such, directlyelectrically connected components do not include components electricallyconnected through active elements, such as transistors or diodes, orthrough capacitors. Directly electrically connected elements may bedirectly physically connected and directly electrically connected.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orboard does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to any materialthat provides incidental heat conduction, but are intended to refer tomaterials that are typically known as good heat conductors or known tohave utility for transferring heat, or components having similar heatconducting properties as those materials.

Embodiments may be described, and illustrated in the drawings, in termsof functional blocks, units and/or modules. Those skilled in the artwill appreciate that these blocks, units and/or modules are physicallyimplemented by electronic (or optical) circuits such as logic circuits,discrete components, analog circuits, hard-wired circuits, memoryelements, wiring connections, and the like, which may be formed usingsemiconductor-based fabrication techniques or other manufacturingtechnologies. In the case of the blocks, units and/or modules beingimplemented by microprocessors or similar, they may be programmed usingsoftware (e.g., microcode) to perform various functions discussed hereinand may optionally be driven by firmware and/or software. Alternatively,each block, unit and/or module may be implemented by dedicated hardware,or as a combination of dedicated hardware to perform some functions anda processor (e.g., one or more programmed microprocessors and associatedcircuitry) to perform other functions. Also, each block, unit and/ormodule of the embodiments may be physically separated into two or moreinteracting and discrete blocks, units and/or modules. Further, theblocks, units and/or modules of the various embodiments may bephysically combined into more complex blocks, units and/or modules.

If any terms in this application conflict with terms used in anyapplication(s) from which this application claims priority, or termsincorporated by reference into this application or the application(s)from which this application claims priority, a construction based on theterms as used or defined in this application should be applied.

It should be noted that, the following description of variousembodiments of the present disclosure is described herein in order toclearly illustrate the inventive features of the present disclosure.However, it is not intended that various embodiments can only beimplemented alone. Rather, it is contemplated that various of thedifferent embodiments can be and are intended to be used together in afinal product, and can be combined in various ways to achieve variousfinal products. Thus, people having ordinary skill in the art maycombine the possible embodiments together or replace thecomponents/modules between the different embodiments according to designrequirements. The embodiments taught herein are not limited to the formdescribed in the following examples, any possible replacement andarrangement between the various embodiments are included.

Applicant's prior U.S. patent application Ser. No. 14/724,840 (US PGPUbNo. 2016/0091156, the disclosure of which is incorporated herein in itsentirety by reference), as an illustrated example, has addressed certainissues associated with the occurrence of electric shock in using aconventional LED lamp by providing a bendable circuit sheet. Some of theembodiments disclosed in U.S. patent application Ser. No. 14/724,840 canbe combined with one or more of the exemplary embodiments disclosedherein to further reduce the occurrence of electric shock in using anLED lamp.

FIG. 1A is a plane cross-sectional view schematically illustrating anLED tube lamp including an LED light strip and a power supply moduleaccording to some exemplary embodiments. Referring to FIG. 1A, an LEDtube lamp may include an LED light strip 2 and a power supply 5, inwhich the power supply 5 can be a modularized element, which means thepower supply 5 can be integrated into a single power supply circuit orcan be integrated into several separated power supply circuits. Forexample, in an embodiment, the power supply 5 can be a single unit(i.e., all components of the power supply 5 are disposed on a singlebody/carrier) disposed in one of the end caps at one end of the lamptube. In another embodiment, the power supply 5 can be two separateunits (i.e., the components of the power supply 5 are divided into twoparts) disposed in different end caps at respective ends of the lamptube.

In the embodiment of FIG. 1A, the power supply 5 is illustrated as beingintegrated into one module for example (hereinafter referred to as apower supply module 5) and is disposed in the end cap parallel to theaxial direction cyd of the lamp tube. More specifically, the axialdirection cyd of the lamp tube, which refers to the direction pointed toby the axis of the lamp tube, is perpendicular to the end wall of theend caps. Disposing the power supply module 5 parallel to the axialdirection cyd means the circuit board, with the electronic components ofthe power supply module, is parallel to the axial direction cyd.Therefore, the normal direction of the circuit board is perpendicular tothe axial direction cyd. In certain embodiments, the power supply module5 can be arranged in a position where the axial direction cyd passes, ina position above the axial plane/axial direction cyd, or in a positionbelow the axial plane/axial direction cyd (relative to the figure). Theinvention is not limited thereto.

FIG. 1B is another plane cross-sectional view schematically illustratingan LED tube lamp including an LED light strip and a power supply moduleaccording to some exemplary embodiments. Referring to FIG. 1B, thedifference between the embodiments of FIGS. 1A and 1B is that the powersupply module 5 illustrated in FIG. 1B is disposed in the end capperpendicular to the axial direction cyd of the lamp tube. For example,the power supply module 5 is disposed parallel to the end wall of theend caps. Although the FIG. 1B shows that the electronic components aredisposed on the side facing the interior of the lamp tube, the inventionis not limited thereto. In certain embodiments, the electronic componentcan be disposed on the side facing the end wall of the corresponding endcap. Under these configurations, since at least one opening can beformed in the end wall of the end caps, the heat dissipation effect ofthe electronic components can be improved through the opening.

In addition, due to the power supply module 5 being vertically disposedin the end caps, the space within the end caps can be increased so thatthe power supply module 5 can be further divided into a plurality ofseparated circuit boards as shown in FIG. 1C. FIG. 1C is still anotherplane cross-sectional view schematically illustrating an LED tube lampincluding an LED light strip and a power supply module according to someexemplary embodiments. The difference between the embodiments of FIGS.1B and 1C is that the power supply 5 is formed by two power supplymodules 5 a and 5 b. The power supply modules 5 a and 5 b are disposedin the end cap perpendicular to the axial direction cyd and arearranged, toward to the end wall of the end cap, along the axialdirection cyd. Specifically, power supply modules 5 a and 5 b arerespectively provided with each having an independent circuit board. Thecircuit boards are connected to each other through one or moreelectrical connection means, so that the overall power supply circuittopology is similar to the embodiment illustrated in FIG. 1A or FIG. 1B.According to the configuration of FIG. 1C, the space within the end capscan be more effectively utilized, such that the circuit layout space canbe increased. In some certain embodiments, the electronic componentsgenerating more heat (e.g., the capacitor and the inductor) can bedisposed on the power supply module 5 b, which is close to the end wall,so as to enhance the heat dissipation effect of the electroniccomponents through the opening on the end cap.

In certain embodiments, the circuit boards of the power supply modules 5a and 5 b can be designed as a disk shape structure (not shown). Thedisk-shaped circuit boards are disposed in the same end cap along thesame axis. For example, the maximum outer diameter of the circuit boardsmay be slightly smaller than the inner diameter of the end cap and thenormal direction of the disk plane is substantially parallel to theradial direction of the end cap, so that the disk-shaped circuit boardscan be disposed into the space of the end cap. In certain embodiments,at least a DC-to-DC converter circuit and a conversion control IC (i.e.,lighting control circuit) are disposed on the disk-shaped circuit boardof the power supply module 5 a, and at least a fuse, a EMI module, arectifying circuit and an installation detection module are disposed onthe disk-shaped circuit board of the power supply module 5 b. Thedisk-shaped circuit board of the power supply module 5 b is disposedclose to the side wall of the end cap (in relation to the power supplymodule 5 a and other components of the LED tube lamp) and electricallyconnected to the conduction pins on the end cap. The disk-shaped circuitboards of the power supply modules 5 a and 5 b are electricallyconnected to each other. The disk-shaped circuit board of the powersupply module 5 a is electrically connected to the LED light strip 2.

In certain embodiments, in order to vertically dispose the power supplymodules 5 a and 5 b in the cylindrical end caps and maximize the layoutarea, the circuit boards of the power supply modules 5 a and 5 b canadopt an octagon structure. But other shapes can be used.

For the connection means between the power supply modules 5 a and 5 b,the separate power supply modules 5 a and 5 b can be connected to eachother, for example, through a male plug and a female plug or throughbonding a lead. If the lead is utilized to connect the power supplymodules 5 a and 5 b, the outer layer of the lead can be wrapped with aninsulating sleeve to serve as electrical insulation protection. Inaddition, the power supply modules 5 a and 5 b can also be connectedthrough rivets or solder paste, or bound together by wires.

Referring to FIGS. 1A to 1C, an LED tube lamp may include an LED lightstrip 2. In certain embodiments, the LED light strip 2 may be formedfrom a bendable circuit sheet, for example that may be flexible. Asdescribed further below, the bendable circuit sheet is also described asa bendable circuit board. The LED light strip 2, and for example thebendable circuit sheet, may also be a flexible strip, such as a flexibleor non-rigid tape or a ribbon. The bendable circuit sheet may have endsthereof passing across a transition region of the lamp tube of the LEDtube lamp to be connected to a power supply 5. In some embodiments, theends of the bendable circuit sheet may be connected to a power supply inan end cap of the LED tube lamp. For example, the ends may be connectedin a manner such that a portion of the bendable circuit sheet is bentaway from the lamp tube and passes through the transition region where alamp tube narrows, and such that the bendable circuit sheet verticallyoverlaps part of a power supply within an end cap of the LED tube lamp.

A power supply as described herein may include a circuit that convertsor generates power based on a received voltage, in order to supply powerto operate an LED module of the LED tube lamp. A power supply, asdescribed in connection with power supply 5, may be otherwise referredto as a power conversion module or circuit or a power supply module. Apower conversion module or circuit, or power supply module, may supplyor provide power from external signal(s), such as from an AC power lineor from a ballast, to an LED module. For example, a power supply 5 mayrefer to a circuit that converts ac line voltage to dc voltage andsupplies power to the LED or LED module. The power supply 5 may includeone or more power components mounted thereon for converting and/orgenerating power.

FIG. 2 is a block diagram illustrating leads that are disposed betweentwo end caps of an LED tube lamp according to some exemplaryembodiments.

Referring to FIG. 2, in some embodiments, the LED tube lamp includes alamp tube (not shown in FIG. 2), end caps (not shown in FIG. 2), a lightstrip 2, short circuit boards 253 (also referred to as right end shortcircuit board 253 and left end short circuit board 253) respectivelyprovided at two ends of the lamp tube, and an inductive element 526.Each of the lamp tube's two ends may have at least one conductive pin orexternal connection terminal for receiving the external driving signal.The end caps are disposed respectively at the two ends of the lamp tube,and (at least partial electronic components of) the short circuit boards253 shown as located respectively at the left and right ends of the lamptube in FIG. 2 may be disposed respectively in the end caps. The shortcircuit boards may be, for example, a rigid circuit board such asdepicted in and described in connection with FIG. 1 and the variousother rigid circuit boards described herein. For example, these circuitboards may include mounted thereon one or more power supply componentsfor generating and/or converting power to be used to light the LED lightsources on the light strip 2. The light strip 2 is disposed in the lamptube and includes an LED module, which includes an LED unit 632.

For an LED tube lamp, such as an 8 ft. 42 W LED tube lamp, to receive adual-end power supply between two ends of the LED tube lamp, two(partial) power supply circuits (each having a power rating of e.g. 21W, 17.5 W, or 12.5 W) are typically disposed respectively in the two endcaps of the lamp tube, and a lead (typically referred to as lead Line,Neutral and Ground) disposed between two end caps of the lamp tube(e.g., between two conductive pins or external connection terminals atrespective end caps of the lamp tube), connected to the power supplycircuits disposed on the opposite sides of the light strip and as aninput signal line may be needed. The lead Line (also known as the “livewire”) and/or the lead Neutral (also known as the “neutral wire”) may bedisposed along the light strip that may include, e.g., a bendablecircuit sheet or flexible circuit board, for receiving and transmittingan external driving signal from the power supply. This lead Line isdistinct from two leads typically referred to as LED+ and LED− that arerespectively connected to a positive electrode and a negative electrodeof an LED unit in the lamp tube. This lead Line is also distinct from alead Ground (also known as the “earth wire”) which is disposed betweenrespective ground terminals of the LED tube lamp. Because the lead Lineis typically disposed along the light strip, and because parasiticcapacitance(s) (e.g., about 200 pF) may be caused between the lead Lineand the lead LED+ due to their close proximity to each other, some highfrequency signals (not the intended frequency range of signal forsupplying power to the LED module) passing through the lead LED+ will bereflected to the lead Line through the parasitic capacitance(s) and thencan be detected there as undesirable EMI effects. The unfavorable EMIeffects may lower or degrade the quality of power transmission in theLED tube lamp.

Again referring to FIG. 2, in some embodiments, the right and left shortcircuit boards 253 are electrically connected to the light strip 2. Insome embodiments, the electrical connection (such as through solderingor bond pad(s)) between the short circuit boards 253 and the light strip2 may comprise a first terminal (denoted by “L”), a second terminal(denoted by “+” or “LED+”), a third terminal (denoted by “−” or “LED-”),and a fourth terminal (denoted by “GND” or “ground”). The light strip 2includes the first through fourth terminals at a first end of the lightstrip 2 adjacent to the right end short circuit board 253 near one endcap of the lamp tube and includes the first through fourth terminals ata second end, opposite to the first end, of the light strip 2 adjacentto the left end short circuit board 253 near the other end cap of thelamp tube. The right end short circuit board 253 also includes the firstthrough fourth terminals to respectively connect to the first throughfourth terminals of the light strip 2 at the first end of the lightstrip 2. The left end short circuit board 253 also includes the firstthrough fourth terminals to respectively connect to the first throughfourth terminals of the light strip 2 at the second end of the lightstrip 2. For example, the first terminal L is utilized to connect a lead(typically referred to as Line or Neutral) for connecting both of the atleast one pin of each of the two ends of the lamp tube; the secondterminal LED+ is utilized to connect each of the short circuit boards253 to the positive electrode of the LED unit 632 of the LED moduleincluded in the light strip 2. The third terminal LED− is utilized toconnect each of the short circuit boards 253 to the negative electrodeof the LED unit 632 of the LED module included in the light strip 2. Thefourth terminal GND is utilized to connect to a reference potential.Preferably and typically, the reference potential is defined as theelectrical potential of ground. Therefore, the fourth terminal isutilized for a grounding purpose of the power supply module of the LEDtube lamp.

To address the undesirable EMI effects mentioned above caused byparasitic capacitance(s) between the lead Line and the lead LED+,inductive element 526 disposed in the lead Ground serves to reduce orprevent the EMI effects by blocking the forming of a complete circuitbetween the lead LED+ and the Ground lead for the high frequency signalsmentioned above to pass through, since at these high frequenciesinductive element 526 behaves like an open circuit. When the completecircuit is prevented or blocked by inductive element 526, the highfrequency signals will be prevented on the lead LED+ and therefore willnot be reflected to the lead Line, thus preventing the undesirable EMIeffects. In some embodiments, the inductive element 526 is connectedbetween two of the fourth terminals respectively of the right end andleft end short circuit boards 253 at the two ends of the lamp tube. Insome embodiments, the inductive element 526 may comprise an inductorsuch as a choke inductor or a dual-inline-package inductor capable ofachieving a function of eliminating or reducing the above-mentioned EMIeffects of the lead (“Line”) disposed along the light strip 2 betweentwo of the first terminals (“L”) respectively at two ends of the lamptube. Therefore, this function can improve signal transmission (whichmay include transmissions through leads “L”, “LED+”, and “LED-”) of thepower supply in the LED tube lamp, and thus the qualities of the LEDtube lamp. Therefore, the LED tube lamp comprising the inductive element526 may effectively reduce EMI effects of the lead “L” or “Line”.Moreover, such an LED tube lamp or an LED lighting fixture may furthercomprise an installation detection circuit or module, which is describedbelow with reference to FIGS. 13A and 13B, for detecting whether or notthe LED tube lamp is properly installed in a lamp socket or whether anexternal impedance is electrically connected to the LED tube lamp.

Referring to FIGS. 3A and 3B, in another embodiment, the LED light stripand the power supply may be connected by utilizing a circuit boardassembly 25 configured with a power supply module 250 instead of solderbonding as described previously. The circuit board assembly 25 has along circuit sheet 251 and a short circuit board 253 that are adhered toeach other with the short circuit board 253 being adjacent to the sideedge of the long circuit sheet 251. The short circuit board 253 may beprovided with the power supply module 250 to form the power supply. Theshort circuit board 253 is stiffer or more rigid than the long circuitsheet 251 to be able to support the power supply module 250.

The long circuit sheet 251 may be the bendable circuit sheet of the LEDlight strip 2 including a wiring layer. The wiring layer 2 a of the LEDlight strip 2 and the power supply module 250 may be electricallyconnected in various manners depending on the demand in practice. Asshown in FIG. 3A, the power supply module 250 and the long circuit sheet251 having the wiring layer 2 a on surface are on the same side of theshort circuit board 253 such that the power supply module 250 isdirectly connected to the long circuit sheet 251. As shown in FIG. 3B,alternatively, the power supply module 250 and the long circuit sheet251 including the wiring layer 2 a on surface are on opposite sides ofthe short circuit board 253 such that the power supply module 250 isdirectly connected to the short circuit board 253 and indirectlyconnected to the wiring layer 2 a of the LED light strip 2 by way of theshort circuit board 253.

The power supply module 250 and power supply 5 described above mayinclude various elements for providing power to the LED light strip 2.For example, they may include power converters or other circuit elementsand/or components for providing power to the LED light strip 2. Also, itshould be noted that the power supply 5 depicted and discussed in FIG. 1may also include a power supply module 250, though one is not labeled inFIG. 1. For example, the power supply module may be mounted on thecircuit board, as shown in FIG. 1, and may include power converters orother circuit elements and/or components for providing power to the LEDlight strip 2.

FIG. 4A is a block diagram of a system including an LED tube lampincluding a power supply module according to certain embodiments.Referring to FIG. 4A, an alternating current (AC) power supply 508 isused to supply an AC supply signal, and may be an AC power line with avoltage rating, for example, in 100-277V and a frequency rating, forexample, of 50 Hz or 60 Hz. A lamp driving circuit 505 receives the ACsupply signal from the AC power supply 508 and then converts it into anAC driving signal. The power supply module and power supply 508described above may include various elements for providing power to theLED light strip 2. For example, they may include power converters orother circuit elements for providing power to the LED light strip 2. Insome embodiments, the power supply 508 and the lamp driving circuit 505are outside of the LED tube lamp. For example, the lamp driving circuit505 may be part of a lamp socket or lamp holder into which the LED tubelamp is inserted. The lamp driving circuit 505 could be an electronicballast and may be used to convert the signal of commercial electricityinto high-frequency and high-voltage AC driving signal. The common typesof electronic ballast, such as instant-start electronic ballast,program-start electronic ballast, and rapid-start electronic ballast,can be applied to the LED tube lamp. In some embodiments, the voltage ofthe AC driving signal is bigger than 300V and in some embodiments400-700V with frequency being higher than 10 kHz and in some embodiments20-50 kHz. An LED tube lamp 500 receives the AC driving signal from thelamp driving circuit 505 and is thus driven to emit light. In thepresent embodiment, the LED tube lamp 500 is in a driving environment inwhich it is power-supplied at its one end cap having two conductive pins501 and 502 (which can be referred to the external connectionterminals), which are used to receive the AC driving signal. The twopins 501 and 502 may be electrically coupled to, either directly orindirectly, the lamp driving circuit 505.

In some embodiments, the lamp driving circuit 505 may be omitted and istherefore depicted by a dotted line. In certain embodiments, if the lampdriving circuit 505 is omitted, the AC power supply 508 is directlycoupled to the pins 501 and 502, which then receive the AC supply signalas the AC driving signal.

In an alternative to the application of the single-end power supplymentioned above, the LED tube lamp may be power-supplied at its both endcaps respectively having two conductive pins, which are coupled to thelamp driving circuit to concurrently receive the AC driving signal.Under the structure where the LED tube lamp having two end caps and eachend cap has two conductive pins, the LED tube lamp can be designed forreceiving the AC driving signal by one pin in each end cap, or by twopins in each end cap.

An example of a circuit configuration of the power supply modulereceiving the AC driving signal by one pin in each end cap can be seenin FIG. 4B (referred to as a “dual-end-single-pin configuration”hereinafter), which illustrates a block diagram of an exemplary powersupply module for an LED tube lamp according to some exemplaryembodiments. Referring to FIG. 4B, each end cap of the LED tube lamp 500could have only one conductive pin for receiving the AC driving signal.For example, it is not required to have two conductive pins used in eachend cap for the purpose of passing electricity through the both ends ofthe LED tube lamp. Compared to FIG. 4A, the conductive pins 501 and 502in FIG. 4B are correspondingly configured at both end caps of the LEDtube lamp 500, and the AC power supply 508 and the lamp driving circuit505 are the same as those mentioned above.

The circuit configuration of the power supply module receiving the ACdriving signal by two pins in each end cap can be referred to FIG. 4C(referred to “dual-end-dual-pin configuration” hereinafter), whichillustrates a block diagram of an exemplary power supply module for anLED tube lamp according to some exemplary embodiments. Compared to FIG.4A and FIG. 4B, the present embodiment further includes pins 503 and504. One end cap of the lamp tube has the pins 501 and 502, and theother end cap of the lamp tube has the pins 503 and 504. The pins 501 to504 are connected to the lamp driving circuit 505 to collectivelyreceive the AC driving signal, and thus the LED light sources (notshown) in the LED tube lamp 500 are driven to emit light.

Under the dual-end-dual-pin configuration, no matter whether the ACdriving signal is provided to two pins on one of the end caps, one pinon each end cap, or two pins on each end cap, the AC driving signal canbe used for the operating power of the LED tube lamp by rearranging thecircuit configuration of the power supply module. When the AC drivingsignal is provided to one pin on each end cap (i.e., differentpolarities of the AC driving signal are respectively provided to the twoend caps), in an exemplary embodiment, another one pin on each end capis set to a floating state. For example, the pins 502 and 503 can be setto the floating state, so that the tube lamp receives the AC drivingsignal via the pins 501 and 504. The power supply module performsrectification and filtering to the AC driving signal received from thepins 501 and 504. In another exemplary embodiment, both pins on the sameend cap are connected to each other, for example, the pin 501 isconnected to the pin 502 on the left end cap, and the pin 503 isconnected to the pin 504 on the right end cap. Therefore, the pins 501and 502 can be used for receiving the positive or negative AC drivingsignal, and the pins 503 and 504 can be used for receiving the ACdriving signal having opposite polarity with the signal received by thepins 501 and 502. Thus, the power supply module within the tube lamp mayperform the rectification and filtering to the received signal. When theAC driving signal is provided to two pins on each end cap, the pins onthe same side may receive the AC driving signal having differentpolarity. For example, the pins 501 and 502 may receive the AC drivingsignal having opposite polarity, the pins 503 and 504 may receive the ACdriving signal having opposite polarity, and the power supply modulewithin the tube lamp may perform the rectification and filtering to thereceived signal.

FIG. 5A is a block diagram of an exemplary power supply module in an LEDlamp according to some embodiments. Referring to FIG. 5A, the powersupply module 5 is coupled to an LED module 50 in the LED tube lamp 500and includes a rectifying circuit 510 (also referred to as firstrectifying circuit 510), a filtering circuit 520, and a driving circuit530. The rectifying circuit 510 is coupled to a first pin 501 and asecond pin 502 at one end, for receiving and then rectifying an externaldriving signal in order to output or produce a rectified signal at afirst rectifying output terminal 511 and a second rectifying outputterminal 512. The external driving signal in this embodiment may be anAC power signal provided by an AC power supply 508 under any of thepower-supply configurations of FIG. 4A-4C, or even be a DC signalcompatible with or suitable for normal operations of the LED tube lamp500. The filtering circuit 520 is coupled to the rectifying circuit 510for performing filtering of the rectified signal. Specifically, thefiltering circuit 520 is coupled to the first rectifying output terminal511 and second rectifying output terminal 512 in order to receive andthen filter the rectified signal, and then outputs or produces afiltered signal at a first filtering output terminal 521 and a secondfiltering output terminal 522. The driving circuit 530 is coupled to theLED module 50 and the filtering circuit 520, in order to receive thefiltered signal and then produce a driving signal for driving the LEDmodule 50 to emit light. The driving circuit 530 includes e.g. aDC-to-DC converter circuit for converting the received filtered signalinto the driving signal, which is output at a first driving outputterminal 531 and a second driving output terminal 532. In FIG. 5A, thedriving circuit 530 is coupled to the first filtering output terminal521 and second filtering output terminal 522 in order to receive thefiltered signal and then drive LEDs (not illustrated) in the LED tubelamp 500 to emit light. The operation(s) of embodiments of the drivingcircuit 530 is further described in more detail below. The LED module 50is coupled to the first driving output terminal 531 and second drivingoutput terminal 532 in order to receive the driving signal to emitlight, for which the electrical current flowing on or through the LEDmodule 50 is preferably stable at a set or defined current value. Insome embodiments, an LED module being driven to emit light can refer tolumens of the LED module reaching at least fifty percent of the lumenoutput indicated by the manufacturer, also described as nominal lumens(e.g., at least fifty percent of the lumens expected to be output underfull power operating conditions). Details of these operations aredescribed below according to some certain embodiments.

FIG. 5B is a block diagram of an exemplary power supply module in an LEDlamp according to some exemplary embodiments. Referring to FIG. 5B, thepower supply module 5 is coupled to an LED module 50 in the LED tubelamp and includes a first rectifying circuit 510, a filtering circuit520, a driving circuit 530, and another rectifying circuit 540 (alsoreferred to as second rectifying circuit 540). The power supply module 5of FIG. 5B can be utilized in the single-end power supply configurationillustrated in FIG. 4A or the dual-end power supply configurationillustrated in FIGS. 4B and 4C. The first rectifying circuit 510 iscoupled to the pins 501 and 502 to receive and then rectify an externaldriving signal transmitted by the pins 501 and 502; the secondrectifying circuit 540 is coupled to the pins 503 and 504 to receive andthen rectify an external driving signal transmitted by pins 503 and 504.The first rectifying circuit 510 and the second rectifying circuit 540of the power supply module collectively output a rectified signal at tworectifying circuit output terminals 511 and 512. The filtering circuit520 is coupled to the rectifying circuit output terminals 511 and 512 toreceive and then filter the rectified signal, so as to output a filteredsignal at two filtering output terminals 521 and 522. The drivingcircuit 530 is coupled to the first filtering output terminal 521 andsecond filtering output terminal 522 in order to receive the filteredsignal and then drive LEDs (not illustrated) in the LED tube lamp 500 toemit light.

FIG. 5C is a block diagram of an exemplary LED lamp according to someexemplary embodiments. Referring to FIG. 4F, the power supply module ofLED tube lamp includes a rectifying circuit 510, a filtering circuit 520and a driving circuit 530, which can also be utilized in the single-endpower supply configuration illustrated in FIG. 4A or the dual-end powersupply configuration illustrated in FIGS. 4B and 4C. The differencebetween the embodiments illustrated in FIG. 5C and FIG. 5B is that therectifying circuit 510 has three input terminals to be coupled to thepins 501 to 503, respectively. The rectifying circuit 510 rectifies thesignals received from the pins 501 to 503, in which the pin 504 can beset to the floating state or connected to the pin 503. Therefore, thesecond rectifying circuit 540 can be omitted in the present embodiment.The rest of circuitry operates substantially the same as the embodimentillustrated in FIG. 5B, so that the detailed description is not repeatedherein.

Although there are two rectifying output terminals 511 and 512 and twofiltering output terminals 521 and 522 in the embodiments of theseFIGS., in practice the number of ports or terminals for coupling betweenthe rectifying circuit 510, the filtering circuit 520, the drivingcircuit 530 and the LED module 50 may be one or more depending on theneeds of signal transmission between the circuits or devices.

In addition, the power supply module of the LED lamp described in FIG.5A, and embodiments of a power supply module of an LED lamp describedbelow, may each be used in the LED tube lamp 500 in FIGS. 4A and 4B, andmay instead be used in any other type of LED lighting structure havingtwo conductive pins used to conduct power, such as LED light bulbs,personal area lights (PAL), plug-in LED lamps with different types ofbases (such as types of PL-S, PL-D, PL-T, PL-L, etc.), etc. Further, theimplementation for LED light bulbs may provide better effects onprotecting from electric shock as combining this invention and thestructures disclosed in PCT patent application WO2016045631.

When the LED tube lamp 500 is applied to the dual-end power structurewith at least one pin, retrofit can be performed to a lamp socketincluding a lamp driving circuit 505, so as to bypass the lamp drivingcircuit 505 and provide the AC power supply (e.g., commercialelectricity) or the DC power supply as the power source of the LED tubelamp.

FIG. 6A is a schematic diagram of an LED module according to anembodiment. Referring to FIG. 6A, an LED module 50 has an anodeconnected to a driving output terminal 531, a cathode connected to adriving output terminal 522, and includes at least one LED unit 632,such as the light source mentioned above. When two or more LED units areincluded, they are connected in parallel. The anode of each LED unit 632is connected to the anode of LED module 50 to couple with the drivingoutput terminal 531, and the cathode of each LED unit 632 is connectedto the cathode of LED module 50 to couple to the driving output terminal532. Each LED unit 632 includes at least one LED 631. When multiple LEDs631 are included in an LED unit 632, they are connected in series withthe anode of the first LED 631 connected to the anode of this LED unit632 (the anode of the first LED 631 and the anode of the LED unit 632may be the same terminal) and the cathode of the first LED 631 connectedto the next or second LED 631. And the anode of the last LED 631 in thisLED unit 632 is connected to the cathode of a previous LED 631 and thecathode of the last LED 631 connected to the cathode of this LED unit632 (the cathode of the last LED 631 and the cathode of the LED unit 632may be the same terminal).

In some embodiments, the LED module 50 may produce a current detectionsignal S531 reflecting the magnitude of current through the LED module50 and being used for controlling or detecting the LED module 50.

FIG. 6B is a schematic diagram of an LED module according to anexemplary embodiment. Referring to FIG. 6B, an LED module 50 has ananode connected to a filtering output terminal 521, a cathode connectedto a filtering output terminal 522, and includes at least two LED units732 with the anode of each LED unit 732 connected to the anode of LEDmodule 50 and the cathode of each LED unit 732 connected to the cathodeof LED module 50 (the anode of each LED unit 732 and the anode of theLED module 50 may be the same terminal, and the cathode of each LED unit732 and the cathode of the LED module 50 may be the same terminal). EachLED unit 732 includes at least two LEDs 731 connected in the same way asthose described in FIG. 6A. For example, the anode of the first LED 731in an LED unit 732 is connected to the anode of this LED unit 732, thecathode of the first LED 731 is connected to the anode of the next orsecond LED 731, and the cathode of the last LED 731 is connected to thecathode of this LED unit 732. Further, LED units 732 in an LED module 50are connected to each other in this embodiment. All of the n-th LEDs 731in the related LED units 732 thereof are connected by their anodes andcathodes, such as those shown in FIG. 6B but not limit to, where n is apositive integer. In this way, the LEDs in the LED module 50 of thisembodiment are connected in the form of a mesh.

In some embodiments, the number of LEDs 731 included by an LED unit 732is in the range of 15-25, and may be in some embodiments in the range of18-22.

FIG. 7A is a schematic circuit diagram of a rectifying circuit accordingto an embodiment. Referring to FIG. 7A, a rectifying circuit 610, i.e. abridge rectifier, includes four rectifying diodes 611, 612, 613, and614, configured to full-wave rectify a received signal. The diode 611has an anode connected to the output terminal 512, and a cathodeconnected to the pin 502. The diode 612 has an anode connected to theoutput terminal 512, and a cathode connected to the pin 501. The diode613 has an anode connected to the pin 502, and a cathode connected tothe output terminal 511. The diode 614 has an anode connected to the pin501, and a cathode connected to the output terminal 511.

When the pins 501 and 502 receive an AC signal, the rectifying circuit610 operates as follows. During the connected AC signal's positive halfcycle, the AC signal is input through the pin 501, the diode 614, andthe output terminal 511 in sequence, and later output through the outputterminal 512, the diode 611, and the pin 502 in sequence. During theconnected AC signal's negative half cycle, the AC signal is inputthrough the pin 502, the diode 613, and the output terminal 511 insequence, and later output through the output terminal 512, the diode612, and the pin 501 in sequence. Therefore, during the connected ACsignal's full cycle, the positive pole of the rectified signal producedby the rectifying circuit 610 keeps at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the rectified signal produced or output by therectifying circuit 610 is a full-wave rectified signal.

When the pins 501 and 502 are coupled to a DC power supply to receive aDC signal, the rectifying circuit 610 operates as follows. When the pin501 is coupled to the positive end of the DC power supply and the pin502 to the negative end of the DC power supply, the DC signal is inputthrough the pin 501, the diode 614, and the output terminal 511 insequence, and later output through the output terminal 512, the diode611, and the pin 502 in sequence. When the pin 501 is coupled to thenegative end of the DC power supply and the pin 502 to the positive endof the DC power supply, the DC signal is input through the pin 502, thediode 613, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 612, and the pin 501 insequence. Therefore, no matter what the electrical polarity of the DCsignal is between the pins 501 and 502, the positive pole of therectified signal produced by the rectifying circuit 610 keeps at theoutput terminal 511, and the negative pole of the rectified signalremains at the output terminal 512.

Therefore, the rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 7B is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 7B, a rectifying circuit 710 includes tworectifying diodes 711 and 712, configured to half-wave rectify areceived signal. The rectifying diode 711 has an anode connected to thepin 502, and a cathode connected to the rectifying output terminal 511.The rectifying diode 712 has an anode connected to the rectifying outputterminal 511, and a cathode connected to the pin 501. The rectifyingoutput terminal 512 can be omitted or connect to ground according to thepractical application. Detailed operations of the rectifying circuit 710are described below.

During the connected AC signal's positive half cycle, the signal levelof the AC signal input through the pin 501 is greater than the signallevel of the AC signal input through the pin 502. At that time, both therectifying diodes 711 and 712 are cut off since being reverse biased,and thus the rectifying circuit 710 stops outputting the rectifiedsignal. During the connected AC signal's negative half cycle, the signallevel of the AC signal input through the pin 501 is less than the signallevel of the AC signal input through the pin 502. At that time, both therectifying diodes 711 and 712 are conducting since they are forwardbiased, and thus the AC signal is input through the pin 502, therectifying diode 711, and the rectifying output terminal 511 insequence, and later output through the rectifying output terminal 512 oranother circuit or ground of the LED tube lamp. Accordingly, therectified signal produced or output by the rectifying circuit 710 is ahalf-wave rectified signal.

It should be noted that, when the pins 501 and 502 shown in FIG. 7A andFIG. 7B are respectively changed to the pins 503 and 504, the rectifyingcircuit 610 and 710 can be considered as the rectifying circuit 540illustrated in FIG. 5B. More specifically, in an exemplary embodiment,when the full-wave rectifying circuit 610 shown in FIG. 7A is applied tothe dual-end tube lamp shown in FIG. 5B, the configuration of therectifying circuits 510 and 540 is shown in FIG. 7C. FIG. 7C is aschematic diagram of a rectifying circuit according to an embodiment.

Referring to FIG. 7C, the rectifying circuit 640 has the sameconfiguration as the rectifying circuit 610, which is the bridgerectifying circuit. The rectifying circuit 610 includes four rectifyingdiodes 611 to 614, which has the same configuration as the embodimentillustrated in FIG. 7A. The rectifying circuit 640 includes fourrectifying diodes 641 to 644 and is configured to perform full-waverectification on the received signal. The rectifying diode 641 has ananode coupled to the rectifying output terminal 512, and a cathodecoupled to the pin 504. The rectifying diode 642 has an anode coupled tothe rectifying output terminal 512, and a cathode coupled to the pin503. The rectifying diode 643 has an anode coupled to the pin 502, and acathode coupled to the rectifying output terminal 511. The rectifyingdiode 644 has an anode coupled to the pin 503, and a cathode coupled tothe rectifying output terminal 511.

In the present embodiment, the rectifying circuits 610 and 640 areconfigured to correspond to each other, in which the difference betweenthe rectifying circuits 610 and 640 is that the input terminal of therectifying circuit 610 (which can be used as the rectifying circuit 510shown in FIG. 5B) is coupled to the pins 501 and 502, but the inputterminal of the rectifying circuit 640 (which can be used as therectifying circuit 540 shown in FIG. 5B) is coupled to the pins 503 and504. Therefore, the present embodiment applies a structure including twofull-wave rectifying circuits for implementing the dual-end-dual-pincircuit configuration.

In some embodiments, in the rectifying circuit illustrated in theexample of FIG. 7C, although the circuit configuration is disposed asthe dual-end-dual-pin configuration, the external driving signal is notlimited to be provided through both pins on each end cap. Under theconfiguration shown in FIG. 7C, no matter whether the AC signal isprovided through both pins on single end cap or through signal pin oneach end cap, the rectifying circuit shown in FIG. 7C may correctlyrectify the received signal and generate the rectified signal forlighting the LED tube lamp. Detailed operations are described below.

When the AC signal is provided through both pins on single end cap, theAC signal can be applied to the pins 501 and 502, or to the pins 503 and504. When the AC signal is applied to the pins 501 and 502, therectifying circuit 610 performs full-wave rectification on the AC signalbased on the operation illustrated in the embodiment of FIG. 7A, and therectifying circuit 640 does not operate. On the contrary, when theexternal driving signal is applied to the pins 503 and 504, therectifying circuit 640 performs full-wave rectification on the AC signalbased on the operation illustrated in the embodiment of FIG. 7A, and therectifying circuit 610 does not operate.

When the AC signal is provided through a single pin on each end cap, theAC signal can be applied to the pins 501 and 504, or to the pins 502 and503. For example, the dual pins on each end cap can be arranged based onstandard socket configuration so that the AC signal will be applied toeither pins 501 and 504 or pins 502 and 503, but not pins 501 and 503 orpins 502 and 504 (e.g., based on the physical positioning of the pins oneach end cap).

When the AC signal is applied to the pins 501 and 504, during the ACsignal's positive half cycle (e.g., the voltage at pin 501 is higherthan the voltage at pin 504), the AC signal is input through the pin501, the diode 614, and the output terminal 511 in sequence, and lateroutput through the output terminal 512, the diode 641, and the pin 504in sequence. In this manner, output terminal 511 remains at a highervoltage than output terminal 512. During the AC signal's negative halfcycle (e.g., the voltage at pin 504 is higher than the voltage at pin501), the AC signal is input through the pin 504, the diode 643, and theoutput terminal 511 in sequence, and later output through the outputterminal 512, the diode 612, and the pin 501 in sequence. In thismanner, output terminal 511 still remains at a higher voltage thanoutput terminal 512. Therefore, during the AC signal's full cycle, thepositive pole of the rectified signal remains at the output terminal511, and the negative pole of the rectified signal remains at the outputterminal 512. Accordingly, the diodes 612 and 614 of the rectifyingcircuit 610 and the diodes 641 and 643 of the rectifying circuit 640 areconfigured to perform the full-wave rectification on the AC signal andthus the rectified signal produced or output by the diodes 612, 614,641, and 643 is a full-wave rectified signal.

On the other hand, when the AC signal is applied to the pins 502 and503, during the AC signal's positive half cycle (e.g., the voltage atpin 502 is higher than the voltage at pin 503), the AC signal is inputthrough the pin 502, the diode 613, and the output terminal 511 insequence, and later output through the output terminal 512, the diode642, and the pin 503. During the AC signal's negative half cycle (e.g.,the voltage at pin 503 is higher than the voltage at pin 502), the ACsignal is input through the pin 503, the diode 644, and the outputterminal 511 in sequence, and later output through the output terminal512, the diode 611, and the pin 502 in sequence. Therefore, during theAC signal's full cycle, the positive pole of the rectified signalremains at the output terminal 511, and the negative pole of therectified signal remains at the output terminal 512. Accordingly, thediodes 611 and 613 of the rectifying circuit 610 and the diodes 642 and644 of the rectifying circuit 640 are configured to perform thefull-wave rectification on the AC signal and thus the rectified signalproduced or output by the diodes 611, 613, 642, and 644 is a full-waverectified signal.

When the AC signal is provided through two pins on each end cap, theoperation in each of the rectifying circuits 610 and 640 can be referredto the embodiment illustrated in FIG. 7A, and it will not be repeatedherein. The rectified signal produced by the rectifying circuits 610 and640 is output to the rear-end circuit after superposing on the outputterminals 511 and 512.

In an exemplary embodiment, the rectifying circuit 510 illustrated inFIG. 5C can be implemented by the configuration illustrated in FIG. 7D.FIG. 7D is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 7D, the rectifying circuit 910 includesdiodes 911 to 914, which are configured as the embodiment illustrated inFIG. 7A. In the present embodiment, the rectifying circuit 910 furtherincludes rectifying diodes 915 and 916. The diode 915 has an anodecoupled to the rectifying output terminal 512, and a cathode coupled tothe pin 503. The diode 916 has an anode coupled to the pin 503, and acathode coupled to the rectifying output terminal 511. The pin 504 isset to the float state in the present embodiment.

Specifically, the rectifying circuit 910 can be regarded as a rectifyingcircuit including three sets of bridge arms, in which each of the bridgearms provides an input signal receiving terminal. For example, thediodes 911 and 913 constitute a first bridge arm for receiving thesignal on the pin 502; the diodes 912 and 914 constitute a second bridgearm for receiving the signal on the pin 501; and the diodes 915 and 916constitute a third bridge arm for receiving the signal on the pin 503.According to the rectifying circuit 910 illustrated in FIG. 7D, thefull-wave rectification can be performed as long as different polarityAC signal is respectively received by two of the bridge arms.Accordingly, under the configuration illustrated in FIG. 7D, no matterwhat kind of power supply configuration, such as the AC signal beingprovided to both pins on single end cap, a single pin on each end cap,or both pins on each end cap, the rectifying circuit 910 is compatiblefor producing the rectified signal, correctly. Detailed operations ofthe present embodiment are described below.

When the AC signal is provided through both pins on single end cap, theAC signal can be applied to the pins 501 and 502. The diodes 911 to 914perform full-wave rectification on the AC signal based on the operationillustrated in the embodiment of FIG. 7A, and the diodes 915 and 916 donot operate.

When the AC signal is provided through single pin on each end cap, theAC signal can be applied to the pins 501 and 503, or to the pins 502 and503. When the AC signal is applied to the pins 501 and 503, during theAC signal's positive half cycle (e.g., when the signal on pin 501 has agreater voltage than the signal on pin 503), the AC signal is inputthrough the pin 501, the diode 914, and the output terminal 511 insequence, and later output through the output terminal 512, the diode915, and the pin 503 in sequence. During the AC signal's negative halfcycle (e.g., when the signal on pin 503 has a greater voltage than thesignal on pin 501), the AC signal is input through the pin 503, thediode 916, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 912, and the pin 501 insequence. Therefore, during the AC signal's full cycle, the positivepole of the rectified signal remains at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the diodes 912, 914, 915, and 916 of the rectifyingcircuit 910 are configured to perform the full-wave rectification on theAC signal and thus the rectified signal produced or output by the diodes912, 914, 915, and 916 is a full-wave rectified signal.

On the other hand, when the AC signal is applied to the pins 502 and503, during the AC signal's positive half cycle (e.g., when the signalon pin 502 has a greater voltage than the signal on pin 503), the ACsignal is input through the pin 502, the diode 913, and the outputterminal 511 in sequence, and later output through the output terminal512, the diode 915, and the pin 503. During the AC signal's negativehalf cycle (e.g., when the signal on pin 503 has a greater voltage thanthe signal on pin 502), the AC signal is input through the pin 503, thediode 916, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 911, and the pin 502 insequence. Therefore, during the AC signal's full cycle, the positivepole of the rectified signal remains at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the diodes 911, 913, 915, and 916 of the rectifyingcircuit 910 are configured to perform the full-wave rectification on theAC signal and thus the rectified signal produced or output by the diodes911, 913, 915, and 916 is a full-wave rectified signal.

When the AC signal is provided through two pins on each end cap, theoperation of the diodes 911 to 914 can be referred to the embodimentillustrated in FIG. 7A, and it will not be repeated herein. Also, if thesignal polarity of the pin 503 is the same as the pin 501, the operationof the diodes 915 and 916 is similar to that of the diodes 912 and 914(i.e., the first bridge arm). On the other hand, if the signal polarityof the pin 503 is the same as that of the pin 502, the operation of thediodes 915 and 916 is similar with the diodes 912 and 914 (i.e., thesecond bridge arm).

FIG. 7E is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 7E, the difference between the embodimentsof FIG. 7E and FIG. 7D is that the rectifying circuit shown in FIG. 7Efurther includes a terminal adapter circuit 941. The terminal adaptercircuit 941 includes fuses 947 and 948. One end of the fuse 947 iscoupled to the pin 501, and the other end of the fuse 947 is coupled tothe connection node of the diodes 912 and 914 (i.e., the input terminalof the first bridge arm). One end of the fuse 948 is coupled to the pin502, and the other end of the fuse 948 is coupled to the connection nodeof the diodes 911 and 913 (i.e., the input terminal of the second bridgearm). Accordingly, when the current flowing through any one of the pins501 and 502 is higher than the rated current of the fuses 947 and 948,the fuse 947/948 will be fused (e.g., broken) in response to the currentso as to form an open circuit between the pin 501/502 and the rectifyingcircuit 910, thereby achieving the function of over current protection.In the case of only one of the fuses 947 and 948 being fused (e.g., theover current situation just happens in a brief period and then iseliminated), if the AC driving signal is provided through both pins oneach end cap, the rectifying circuit still works, after the over currentsituation is eliminated, since the AC driving signal can be providedthrough single pin on each end cap.

FIG. 7F is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 7F, the difference between the embodimentsof FIG. 7F and FIG. 7D is that the pins are connected to each otherthrough a thin wire 917. Compared to the embodiments illustrated in FIG.7D or FIG. 7E, when the AC signal is applied to the dual-end-single-pinconfiguration, no matter the AC signal is applied to the pin 503 or thepin 504, the rectifying circuit of the present embodiment can benormally operated. Furthermore, when the pins 503 and 504 are installedin the wrong lamp socket which provides the AC signal to the single endcap, the thin wire 917 can be reliably fused. Therefore, when the lampis installed in the correct lamp socket, the tube lamp utilizing therectifying illustrated in FIG. 7F may keep working, normally.

According to the embodiments mentioned above, the rectifying circuitsillustrated in FIG. 7C to 7F are compatible for receiving the AC signalthrough both pins on single end cap, through single pin on each end cap,and through both pins on each end cap, such that the compatibility ofthe LED tube lamp's application is improved. In this manner, an LED tubelamp can include a rectifying circuit that is arranged to rectify an ACsignal in all of the following situations: when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal throughboth of two pins on a single end cap; when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal throughboth of two pins on each end cap; and when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal through asingle pin on each end cap. In addition, based on the aspect of theactual circuit layout scenario, the embodiments illustrated in FIG. 7Dto 7F require only three power pads for connecting the correspondingpins, so that the process yield can be significant enhanced since themanufacture process of the three pads configuration is easier than thefour power pads configuration.

In some embodiments, one or plural varistors (also known as voltagedependent resistor (VDR)) is disposed on the input side or the outputside of the rectifying circuit. The varistor is configured to protectagainst excessive transient voltages by shunting the current created bythe excessive voltage. According to some embodiments of disposing thevaristor on the input side of the rectifying circuit, the varistor iselectrically connected between the pins 501 and 502. According to someembodiments of disposing the varistor on the output side of therectifying circuit, the varistor is electrically connected between therectifying output terminals 511 and 512. In some embodiments, thevaristor can be designed for smaller size by disposing the varistor onthe output side of the rectifying circuit. In some embodiments, the sizeof the varistor disposed on the output side of the rectifying circuitcan be half of the varistor disposed on the input side of the rectifyingcircuit.

FIG. 8A is a block diagram of the filtering circuit according to anembodiment. A rectifying circuit 510 is shown in FIG. 8A forillustrating its connection with other components, without intending afiltering circuit 520 to include the rectifying circuit 510. Referringto FIG. 8A, the filtering circuit 520 includes a filtering unit 523coupled to two rectifying output terminals 511 and 512 to receive and tofilter out ripples of a rectified signal from the rectifying circuit510. Accordingly, the waveform of a filtered signal is smoother thanthat of the rectified signal. The filtering circuit 520 may furtherinclude another filtering unit 524 coupled between a rectifying circuitand a pin correspondingly, for example, between the rectifying circuit510 and the pin 501, the rectifying circuit 510 and the pin 502, therectifying circuit 540 and the pin 503, and/or the rectifying circuit540 and the pin 504. The filtering unit 524 is used to filter a specificfrequency, for example, to filter out a specific frequency of anexternal driving signal. In this embodiment, the filtering unit 524 iscoupled between the rectifying circuit 510 and the pin 501. Thefiltering circuit 520 may further include another filtering unit 525coupled between one of the pins 501 and 502 and one of the diodes of therectifying circuit 510, or between one of the pins 503 and 504 and oneof the diodes of the rectifying circuit 540 to reduce or filter outelectromagnetic interference (EMI). In this embodiment, the filteringunit 525 is coupled between the pin 501 and one of diodes (not shown inFIG. 8A) of the rectifying circuit 510. Since the filtering units 524and 525 may be present or omitted depending on actual circumstances oftheir uses, they are depicted by a dotted line in FIG. 8A.

FIG. 8B is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 8B, a filtering unit 623 includes acapacitor 625 having an end coupled to the output terminal 511 and afiltering output terminal 521 and the other end thereof coupled to theoutput terminal 512 and a filtering output terminal 522, and isconfigured to low-pass filter a rectified signal from the outputterminals 511 and 512, so as to filter out high-frequency components ofthe rectified signal and thereby output a filtered signal at thefiltering output terminals 521 and 522.

FIG. 8C is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 8C, a filtering unit 723 includes a pifilter circuit including a capacitor 725, an inductor 726, and acapacitor 727. As is well known, a pi-type filter looks like the symbolπ in its shape or structure. The capacitor 725 has an end connected tothe output terminal 511 and coupled to the filtering output terminal 521through the inductor 726, and has another end connected to the outputterminal 512 and the filtering output terminal 522. The inductor 726 iscoupled between output terminal 511 and the filtering output terminal521. The capacitor 727 has an end connected to the filtering outputterminal 521 and coupled to the output terminal 511 through the inductor726, and has another end connected to the output terminal 512 and thefiltering output terminal 522.

As seen between the output terminals 511 and 512 and the filteringoutput terminals 521 and 522, the filtering unit 723 compared to thefiltering unit 623 in FIG. 8B additionally has an inductor 726 and acapacitor 727, which perform the function of low-pass filtering like thecapacitor 725 does. Therefore, the filtering unit 723 in this embodimentcompared to the filtering unit 623 in FIG. 8B has a better ability tofilter out high-frequency components to output a filtered signal with asmoother waveform.

The inductance values of the inductor 726 in the embodiments mentionedabove are chosen in the range of, for example in some embodiments, about10 nH to 10 mH. And the capacitance values of the capacitors 625, 725,and 727 in the embodiments stated above are chosen in the range of, forexample in some embodiments, about 100 pF to 1 uF.

FIG. 8D is a circuit diagram of the filtering circuit according to anembodiment of the present disclosure. Referring to FIG. 8D, theembodiment of FIG. 8D is similar to that of FIG. 8A, with a maindifference that the filtering circuit in FIG. 8D includes a negativevoltage clipping unit 528. The negative voltage clipping unit 528 iscoupled to a filtering unit 523, and is configured to clip, limit, orprevent a negative voltage (or other effects) that might result frompossible resonances of the filtering unit 523, in order to preventdamage due to the negative voltage to a controller or integrated circuitin a later-stage driving circuit. Specifically, the filtering unit 523typically comprises a circuit formed by a resistor, a capacitor, aninductor, or any combination thereof, wherein due to characteristics ofcapacitance and inductance the filtering unit 523 exhibits pureresistive qualities at or close to a specific frequency at the resonancepoint. At the resonance point a signal received by the filtering unit523 will be amplified and output, so a phenomenon of signal fluctuationswill be observed at the output terminal of the filtering unit 523. Whenthe magnitude of the signal fluctuation is excessive to cause the levelof the negative amplitude of the output of the filtering unit 523 to belower than a ground level, a negative voltage might occur at thefiltering output terminals 521 and 522, which negative voltage will beapplied to a later-stage circuit, imposing risks of damages to thelater-stage circuit.

In this embodiment of FIG. 8D, the negative voltage clipping unit 528may be configured to conduct an energy-releasing loop when the negativevoltage occurs, to cause a reverse current resulting from the negativevoltage to be released through the energy-releasing loop and back to thepower line, thereby preventing the reverse current from flowing to alater-stage circuit. FIG. 8E is a circuit diagram of a filtering unit723 and a negative voltage clipping unit according to an embodiment ofthe present disclosure. Referring to FIG. 8E, in this embodiment thenegative voltage clipping unit is implemented by a diode 728, althoughthe present invention is not limited thereto. When resonance of thefiltering unit 723 does not occur, the first filtering output terminal521 has a voltage level higher than that at the second filtering outputterminal 522, so that the diode 728 is cutoff to prevent a current toflow through. On the other hand, when resonance of the filtering unit723 occurs to cause the negative voltage, the second filtering outputterminal 522 has a voltage level higher than that at the first filteringoutput terminal 521, causing the diode 728 to conduct due to the forwardbias voltage across it, which conduction then releases a reverse currentdue to the negative voltage back to the first filtering output terminal521.

In some embodiments, the LED module 50 in this embodiment may produce acurrent detection signal S531 reflecting the magnitude of currentthrough the LED module 50 and being used for controlling or detectingthe LED module 50.

FIG. 9A is a block diagram of a driving circuit 530 according to a firstembodiment. Referring to FIG. 9A, the driving circuit 530 includes acontroller 533, and a conversion circuit 534 for power conversion basedon a current source, for driving an LED module to emit light. Theconversion circuit 534 includes a switching circuit 535 (also known as apower switch) and an energy storage circuit 536. And the conversioncircuit 534 is coupled to first and second filtering output terminals521 and 522 in order to receive and then convert a filtered signal,under the control by the controller 533, into a driving signal at firstand second driving output terminals 531 and 532 for driving the LEDmodule. Under the control by the controller 533, the driving signaloutput by the conversion circuit 534 comprises a steady current, makingthe LED module emit steady light.

It should be noted that, the connection embodiments of the LED module 50described above is not limited to being utilized in a tube lamp. Theconnection embodiments can be applied to any kind of LED lamp directlypowered by the mains electricity/commercial electricity (i.e., the ACpower without passing a ballast), such as an LED bulb, an LED filamentlamp, an integrated LED lamp, etc. The invention is not limited to thesespecific examples.

FIG. 8B is a block diagram of the driving circuit according to anembodiment. Referring to FIG. 8B, a driving circuit includes acontroller 1531, and a conversion circuit 1532 for power conversionbased on a current source, for driving the LED module to emit light. Theconversion circuit 1532 includes a switching circuit 1535 (also known asa power switch) and an energy storage circuit 1538. And the conversioncircuit 1532 is coupled to the filtering output terminals 521 and 522 toreceive and then convert a filtered signal, under the control by thecontroller 1531, into a lamp driving signal at the driving outputterminals 531 and 532 for driving the LED module. Under the control bythe controller 1531, the lamp driving signal output by the conversioncircuit 1532 comprises a steady current, making the LED module emittingsteady light.

The operation of the driving circuit 530 is further described based onthe signal waveform illustrated in FIGS. 10A to 10D. FIGS. 10A-10D aresignal waveform diagrams of exemplary driving circuits according to someexemplary embodiments, in which FIGS. 10A and 10B illustrate the signalwaveform and the control condition when the driving circuit 530 isoperated in a Continuous-Conduction Mode (CCM) and FIGS. 10C and 10Dillustrate the signal waveform and the control condition when thedriving circuit 530 is operated in a Discontinuous-Conduction Mode(DCM). In signal waveform diagrams, the horizontal axis represents time(represented by a symbol “t”), and the vertical axis represents avoltage or current value (depending on the type of the signal).

The controller 533 can be, for example, a constant current controllerwhich can generate a lighting control signal Slc and adjust the dutycycle of the lighting control signal Slc based on a current detectionsignal Sdet, so that the switch circuit 535 is turned on or off inresponse to the lighting control signal Slc. The energy storage circuit536 is repeatedly charged and discharged according to the on/off stateof the switch circuit 535, so that the driving current ILED received bythe LED module 50 can be stably maintained at a predetermined currentvalue Ipred. In some embodiments, the lighting control signal Slc mayhave fixed signal period Tlc and signal amplitude, and the pulse-onperiod (also known as the pulse width) of each signal period Tlc, suchas Ton1, Ton2 and Ton3, can be adjusted according to the controlrequirement. In the present embodiment, the duty cycle of the lightingcontrol signal Slc represents a ratio of the pulse-on period and thesignal period Tlc. For example, when the pulse-on period Ton1 is 40% ofthe signal period Tlc, the duty cycle of the lighting control signal Slcunder the first signal period Tlc is 0.4.

In addition, the signal level of the current detection signal mayrepresent the magnitude of the current flowing through the LED module50, or represent the magnitude of the current flowing through theswitching circuit 535; the present invention is not limited thereto.

Referring to FIGS. 9A and 10A, FIG. 10A illustrates the signal waveformvariation of the driving circuit 530 during a plurality of signalperiods Tlc when the driving current ILED is smaller than thepredetermined current value Ipred. Specifically, under the first signalperiod Tlc, the switching circuit 535 is turned on during the pulse-onperiod Ton1 in response to the high level voltage of the lightingcontrol signal Slc. In the meantime, the conversion circuit 534 providesthe driving current ILED to the LED module 50 according to an inputpower received from the first and the second filtering output terminals521 and 522, and further charges the energy storage circuit 536 via theturned-on switch circuit 535, so that the current IL flowing through theenergy storage circuit 536 gradually increases. In this manner, duringthe pulse-on period Ton1, the energy storage circuit 536 is charged inresponse to the input power received from the first and the secondfiltering output terminals 521 and 522.

After the pulse-on period Ton1, the switch circuit 535 is turned off inresponse to the low level voltage of the lighting control signal Slc.During a cut-off period of the switch circuit 535, the input poweroutput from the first and the second filtering output terminals 521 and522 would not be provided to the LED module 50, and the driving currentILED is dominated by the energy storage circuit 536 (i.e., the drivingcurrent ILED is generated by the energy storage circuit 536 bydischarging). Due to the energy storage circuit 536 discharging duringthe cut-off period, the current IL is gradually decreased. Therefore,even when the lighting control signal Slc is at the low level (i.e., thedisable period of the lighting control signal Slc), the driving circuit530 continuously supply power to the LED module 50 by discharging theenergy storage circuit 536. In this embodiment, no matter whether theswitch circuit 535 is turned on or off, the driving circuit 530continuously provides a stable driving current ILED to the LED module50, and the current value of the driving current ILED is 11 during thefirst signal period Tlc.

Under the first signal period Tlc, the controller 533 determines thecurrent value 11 of the driving current ILED is smaller than thepredetermined current value Ipred, so that the pulse-on period of thelighting control signal Slc is adjusted to Ton2 when entering the secondsignal period Tlc. The length of the pulse-on period Ton2 equals to thelength of the pulse-on period Ton1 plus a unit period t1.

Under the second signal period Tlc, the operation of the switch circuit535 and the energy storage circuit 536 are similar to the operationunder the first signal period Tlc. The difference of the operationbetween the first and the second signal periods Tlc is the energystorage circuit 536 has relatively longer charging time and shorterdischarging time since the pulse-on period Ton2 is longer than pulse-onperiod Ton1. Therefore, the average current value of the driving currentILED under the second signal period Tlc is increased to a current value12 closer to the predetermined current value Ipred.

Similarly, since the current value 12 of the driving current ILED isstill smaller than the predetermined current value Ipred, the controller533 further adjusts, under the third signal period Tlc, the pulse-onperiod of the lighting control signal Slc to Ton3, in which the lengthof the pulse-on period Ton3 equals to the length of the pulse-on periodTon2 plus the unit period t1. Under the third signal period Ton3, theoperation of the switch circuit 535 and the energy storage circuit 536are similar to the operation under the first and the second signalperiods Tlc. Due to the pulse-on period Ton3 being further increased incomparison with the pulse-on period Ton1 and Ton2, the current value ofthe driving current ILED is increased to 13, and substantially reachesthe predetermined current value Ipred. Since the current value 13 of thedriving current ILED has reached the predetermined current value Ipred,the controller 533 maintains the same duty cycle after the third signalperiod Tlc, so that the driving current ILED can be substantiallymaintained at the predetermined current value Ipred.

Referring to FIGS. 9A and 10B, FIG. 10B illustrates the signal waveformvariation of the driving circuit 530 during a plurality of signalperiods Tlc when the driving current ILED is greater than thepredetermined current value Ipred. Specifically, under the first signalperiod Tlc, the switching circuit 535 is turned on during the pulse-onperiod Ton1 in response to the high level voltage of the lightingcontrol signal Slc. In the meantime, the conversion circuit 534 providesthe driving current ILED to the LED module 50 according to an inputpower received from the first and the second filtering output terminals521 and 522, and further charges the energy storage circuit 536 via theturned-on switch circuit 535, so that the current IL flowing through theenergy storage circuit 536 gradually increases. As a result, during thepulse-on period Ton1, the energy storage circuit 536 is charged inresponse to the input power received from the first and the secondfiltering output terminals 521 and 522.

After the pulse-on period Ton1, the switch circuit 535 is turned off inresponse to the low level voltage of the lighting control signal Slc.During a cut-off period of the switch circuit 535, the input poweroutput from the first and the second filtering output terminals 521 and522 would not be provided to the LED module 50, and the driving currentILED is dominated by the energy storage circuit 536 (i.e., the drivingcurrent ILED is generated by the energy storage circuit 536 bydischarging). Due to the energy storage circuit 536 discharging duringthe cut-off period, the current IL is gradually decreased. Therefore,even when the lighting control signal Slc is at the low level (i.e., thedisable period of the lighting control signal Slc), the driving circuit530 continuously supplies power to the LED module 50 by discharging theenergy storage circuit 536. Accordingly, no matter whether the switchcircuit 535 is turned on or turned off, the driving circuit 530continuously provides a stable driving current ILED to the LED module50, and the current value of the driving current ILED is 14 during thefirst signal period Tlc.

Under the first signal period Tlc, the controller 533 determines thecurrent value 14 of the driving current ILED is greater than thepredetermined current value Ipred, so that the pulse-on period of thelighting control signal Slc is adjusted to Ton2 when entering the secondsignal period Tlc. The length of the pulse-on period Ton2 equals to thelength of the pulse-on period Ton1 minus the unit period t1.

Under the second signal period Tlc, the operation of the switch circuit535 and the energy storage circuit 536 are similar to the operationunder the first signal period Tlc. The difference of the operationbetween the first and the second signal periods Tlc is the energystorage circuit 536 has relatively shorter charging time and longerdischarging time since the pulse-on period Ton2 is shorter than pulse-onperiod Ton1. Therefore, the average current value of the driving currentILED under the second signal period Tlc is decreased to a current value15 closer to the predetermined current value Ipred.

Similarly, since the current value 15 of the driving current ILED isstill greater than the predetermined current value Ipred, the controller533 further adjusts, under the third signal period Tlc, the pulse-onperiod of the lighting control signal Slc to Ton3, in which the lengthof the pulse-on period Ton3 equals to the length of the pulse-on periodTon2 minus the unit period t1. Under the third signal period Tlc, theoperation of the switch circuit 535 and the energy storage circuit 536are similar to the operation under the first and the second signalperiods Tlc. Since the pulse-on period Ton3 is further decreased incomparison with the pulse-on period Ton1 and Ton2, the current value ofthe driving current ILED is decreased to 16, so that the driving currentILED substantially reaches the predetermined current value Ipred. Sincethe current value 16 of the driving current ILED has reached thepredetermined current value Ipred, the controller 533 maintains the sameduty cycle after the third signal period Tlc, so that the drivingcurrent ILED can be substantially maintained on the predeterminedcurrent value Ipred.

According to the above operations, the driving circuit 530 may adjust,by a stepped approach, the pulse-on period/pulse width of the lightingcontrol signal Slc, so that the driving current ILED is graduallyadjusted to be close to the predetermined current value Ipred.Therefore, the constant current output can be realized.

In the present embodiment, the driving circuit 530 is operated in CCMfor example, which means the energy storage circuit 536 will not bedischarged to zero current (i.e., the current IL will not be decreasedto zero) during the cut-off period of the switch circuit 535. Byutilizing the driving circuit 530 operating in CCM to provide power tothe LED module 50, the power provided to the LED module 50 can be morestable and has a low ripple.

The control operation of the driving circuit 530 operating in DCM willbe described below. Referring to FIGS. 9A and 10C, the operation and thesignal waveform of the driving circuit 530 illustrated in FIG. 10C aresimilar to that of FIG. 10A. The difference between the FIGS. 10A and10C is that the driving circuit 530 operates in DCM, so that the energystorage circuit 536 discharges, during the pulse-off time of thelighting control signal Slc, to zero current (i.e., the current ILequals to zero) and then re-charges in the next signal period Tlc. Theother operation of the driving circuit 530 can be referred to theembodiments of FIG. 10A, and will not be described in detail herein.

Referring to FIGS. 9A and 10D, the operation and the signal waveform ofthe driving circuit 530 illustrated in FIG. 10D are similar to that ofFIG. 10B. The difference between the FIGS. 10B and 10D is that thedriving circuit 530 operates in DCM, so that the energy storage circuit536 discharges, during the pulse-off time of the lighting control signalSlc, to zero current (i.e., the current IL decreases to zero) and thenre-charges in the next signal period Tlc. The other operation of thedriving circuit 530 can be referred to the embodiments of FIG. 10B, andwill not be described in detail herein.

By utilizing the driving circuit 530 operating in DCM to provide powerto the LED module 50, the driving circuit 530 may have lower powerconsumption, so as to obtain higher power conversion efficiency.

It's noted that although single-stage DC-to-DC converter circuits aretaken as examples of the driving circuit 530 herein, the inventiondisclosed herein is not limited to using the disclosed single-stageDC-to-DC converter circuits. For example, the driving circuit 530 mayinstead comprise a two-stage driving circuit composed of a power factorcorrection circuit along with a DC-to-DC converter. Therefore, anysuitable power conversion circuit structure that can be used for drivingLED light sources may be applied with the invention.

The embodiments of the power conversion operation described aboveillustrate the inventive features of the present disclosure and theseoperations are not limited for use in a tube lamp. The embodiments ofthe power conversion operation can be applied to any kind of LED lampdirectly powered by the mains electricity/commercial electricity (i.e.,the AC power without passing a ballast), such as, for example an LEDbulb, an LED filament lamp, and an integrated LED lamp. The embodimentstaught herein are not limited to these specific examples and are notlimited to the form described in the above examples, any possiblereplacement and arrangement between the various embodiments areincluded.

FIG. 9B is a schematic diagram of the driving circuit according to anembodiment of the present disclosure. Referring to FIG. 9B, a drivingcircuit 630 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 633 and a conversion circuit. The conversioncircuit includes an inductor 636, a diode 634 for “freewheeling” ofcurrent, a capacitor 637, and a switch 635. The driving circuit 630 iscoupled to the filtering output terminals 521 and 522 to receive andthen convert a filtered signal into a lamp driving signal for driving anLED module connected between the driving output terminals 531 and 532.

In this embodiment, the switch 635 includes a metal-oxide-semiconductorfield-effect transistor (MOSFET) and has a first terminal coupled to theanode of freewheeling diode 634, a second terminal coupled to thefiltering output terminal 522, and a control terminal coupled to thecontroller 633 used for controlling current conduction or cutoff betweenthe first and second terminals of switch 635. The driving outputterminal 531 is connected to the filtering output terminal 521, and thedriving output terminal 532 is connected to an end of the inductor 636,which has another end connected to the first terminal of switch 635. Thecapacitor 637 is coupled between the driving output terminals 531 and532 to stabilize the voltage between the driving output terminals 531and 532. The freewheeling diode 634 has a cathode connected to thedriving output terminal 531.

Next, a description follows as to an exemplary operation of the drivingcircuit 630.

The controller 633 is configured for determining when to turn the switch635 on (in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531.For example, in some embodiments, the controller 633 is configured tocontrol the duty cycle of switch 635 being on and switch 635 being offin order to adjust the size or magnitude of the lamp driving signal. Thecurrent detection signal S535 represents the magnitude of currentthrough the switch 635. The current detection signal S531 represents themagnitude of current through the LED module coupled between the drivingoutput terminals 531 and 532. The controller 633 may control the dutycycle of the switch 635 being on and off, based on, for example, amagnitude of a current detected based on current detection signal S531or S535. As such, when the magnitude is above a threshold, the switchmay be off (cutoff state) for more time, and when magnitude goes belowthe threshold, the switch may be on (conducting state) for more time.According to any of current detection signal S535 or current detectionsignal S531, the controller 633 can obtain information on the magnitudeof power converted by the conversion circuit. When the switch 635 isswitched on, a current of a filtered signal is input through thefiltering output terminal 521, and then flows through the capacitor 637,the driving output terminal 531, the LED module, the inductor 636, andthe switch 635, and then flows out from the filtering output terminal522. During this flowing of current, the capacitor 637 and the inductor636 are performing storing of energy. On the other hand, when the switch635 is switched off, the capacitor 637 and the inductor 636 performreleasing of stored energy by a current flowing from the freewheelingdiode 634 to the driving output terminal 531 to make the LED modulecontinuing to emit light.

In some embodiments, the capacitor 637 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 9B. In someapplication environments, the natural characteristic of an inductor tooppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting the capacitor 637. It should benoted that, according to some embodiments that utilize the non-isolatingdriving circuit for performing power conversion, which means there is notransformer in the driving circuit, the switch 635 is capable of beingcontrolled by detecting the magnitude of the current flowing through theswitch 635 (e.g., the current detection signal S535). In someembodiments where the isolating driving circuit is utilized forperforming power conversion, due to the LED module and the controllerbeing isolated by a transformer, the switch 635 can merely be controlledby detecting the magnitude of the current flowing through the LED module(e.g., the current detection signal S531). In some embodiments where theisolating driving circuit is adopted, a detection resistor (not shown)is required for detecting current flowing through the LED module, and aphoto-coupler (not shown) is required for transmitting the detectionresult to the controller 633 at the primary side as the basis forcontrolling the switch 635.

As described above, because the driving circuit 630 is configured fordetermining when to turn a switch 635 on (in a conducting state) or off(in a cutoff state) according to a current detection signal S535 and/ora current detection signal S531, the driving circuit 630 can maintain astable current flow through the LED module. Therefore, the colortemperature will not change with the current for some LED modules, suchas white, red, blue, or green LED modules. For example, an LED canretain the same color temperature under different illuminationconditions. In some embodiments, because the inductor 636 playing therole of the energy-storing circuit releases the stored power when theswitch 635 cuts off, the voltage/current flowing through the LED moduleremains above a predetermined voltage/current level so that the LEDmodule may continue to emit light maintaining the same colortemperature. In this way, when the switch 635 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly,problems of flickering in the LED module can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

FIG. 9C is a schematic diagram of the driving circuit according to anembodiment of the present disclosure. Referring to FIG. 9C, a drivingcircuit 730 in this embodiment comprises a boost DC-to-DC convertercircuit having a controller 733 and a converter circuit. The convertercircuit includes an inductor 736, a diode 734 for “freewheeling” ofcurrent, a capacitor 737, and a switch 735. The driving circuit 730 isconfigured to receive and then convert a filtered signal from thefiltering output terminals 521 and 522 into a lamp driving signal fordriving an LED module coupled between the driving output terminals 531and 532.

The inductor 736 has an end connected to the filtering output terminal521, and another end connected to the anode of freewheeling diode 734and a first terminal of the switch 735, which has a second terminalconnected to the filtering output terminal 522 and the driving outputterminal 532. The freewheeling diode 734 has a cathode connected to thedriving output terminal 531. And the capacitor 737 is coupled betweenthe driving output terminals 531 and 532.

The controller 733 is coupled to a control terminal of switch 735, andis configured for determining when to turn the switch 735 on (in aconducting state) or off (in a cutoff state), according to a currentdetection signal S535 and/or a current detection signal S531. When theswitch 735 is switched on, a current of a filtered signal is inputthrough the filtering output terminal 521, and then flows through theinductor 736 and the switch 735, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 736 increases with time, with the inductor 736 being in astate of storing energy, while the capacitor 737 enters a state ofreleasing energy, making the LED module continuing to emit light. On theother hand, when the switch 735 is switched off, the inductor 736 entersa state of releasing energy as the current through the inductor 736decreases with time. In this state, the current through the inductor 736then flows through the freewheeling diode 734, the capacitor 737, andthe LED module, while the capacitor 737 enters a state of storingenergy.

In some embodiments, the capacitor 737 is an optional element, so it canbe omitted and is thus depicted as a dotted line in FIG. 9C. When thecapacitor 737 is omitted and the switch 735 is switched on, the currentof inductor 736 does not flow through the LED module, making the LEDmodule not emit light; but when the switch 735 is switched off, thecurrent of inductor 736 flows through the freewheeling diode 734 toreach the LED module, making the LED module emit light. Therefore, bycontrolling the time that the LED module emits light, and the magnitudeof current through the LED module, the average luminance of the LEDmodule can be stabilized to be above a defined value, thus alsoachieving the effect of emitting a steady light. It should be notedthat, according to some embodiments that utilize the non-isolatingdriving circuit for performing power conversion, which means there is notransformer in the driving circuit, the switch 735 is capable of beingcontrolled by detecting the magnitude of the current flowing through theswitch 735 (e.g., the current detection signal S535). In someembodiments where the isolating driving circuit is utilized forperforming power conversion, due to the LED module and the controllerbeing isolated by a transformer, the magnitude of the current flowingthrough the switch 735 cannot be used as a reference for controlling theswitch 735.

For detecting magnitude of current flowing through the switch 735, adetection resistor (not shown) may be disposed between the switch 735and the second filtering output terminal 522, according to someembodiments of the present disclosure. When the switch 735 isconducting, current flowing through the detection resistor will cause avoltage difference across two terminals of the detection resistor, sousing or sending current detection signal S535 to control the controller733 can be based on the voltage across the detection resistor, namelythe voltage difference between the two terminals of the detectionresistor. However, at the instant that the LED tube lamp is powered upor is struck by lightning, for example, a relatively large current (ashigh as 10 A or above) is likely to occur on a circuit loop on theswitch 735 that may damage the detection resistor and the controller733. Therefore, in some embodiments, the driving circuit 730 may furtherinclude a clamping component, which is connected to the detectionresistor. The clamping component performs a clamping operation on thecircuit loop of the detection resistor when a current flowing throughthe detection resistor or the voltage difference across the detectionresistor exceeds a threshold value, so as to limit a current to flowthrough the detection resistor. In some embodiments, the clampingcomponent may comprise for example a plurality of diodes connected inseries and the diode series are connected in parallel with the detectionresistor. In such a configuration, when a large current occurs on acircuit loop on the switch 735, the diode series in parallel with thedetection resistor will quickly conduct current, so as to limit avoltage across the detection resistor to a specific voltage level. Forexample, if the diode series comprises 5 diodes, since the forward biasvoltage of a diode is about 0.7 V, the diode series can clamp thevoltage across the detection resistor to be about 3.5 V.

As described above, because the controller 733 included in the drivingcircuit 730 is coupled to the control terminal of switch 735, and isconfigured for determining when to turn a switch 735 on (in a conductingstate) or off (in a cutoff state), according to a current detectionsignal S535 and/or a current detection signal S531, the driving circuit730 can maintain a stable current flow through the LED module.Therefore, the color temperature may not change with the current forsome LED modules, such as white, red, blue, or green LED modules. Forexample, an LED can retain the same color temperature under differentillumination conditions. In some embodiments, because the inductor 736acting as the energy-storing circuit releases the stored power when theswitch 735 cuts off, the voltage/current flowing through the LED moduleremains above a predetermined voltage/current level so that the LEDmodule may continue to emit light maintaining the same colortemperature. In this way, when the switch 735 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theproblem of flickering in the LED module can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

FIG. 9D is a schematic diagram of the driving circuit according to anexemplary embodiment of the present disclosure. Referring to FIG. 9D, adriving circuit 830 in this embodiment comprises a buck DC-to-DCconverter circuit having a controller 833 and a conversion circuit. Theconversion circuit includes an inductor 836, a diode 834 for“freewheeling” of current, a capacitor 837, and a switch 835. Thedriving circuit 830 is coupled to the filtering output terminals 521 and522 to receive and then convert a filtered signal into a lamp drivingsignal for driving an LED module connected between the driving outputterminals 531 and 532.

The switch 835 has a first terminal coupled to the filtering outputterminal 521, a second terminal coupled to the cathode of freewheelingdiode 834, and a control terminal coupled to the controller 833 toreceive a control signal from the controller 833 for controlling currentconduction or cutoff between the first and second terminals of theswitch 835. The anode of freewheeling diode 834 is connected to thefiltering output terminal 522 and the driving output terminal 532. Theinductor 836 has an end connected to the second terminal of switch 835,and another end connected to the driving output terminal 531. Thecapacitor 837 is coupled between the driving output terminals 531 and532 to stabilize the voltage between the driving output terminals 531and 532.

The controller 833 is configured for controlling when to turn the switch835 on (in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531.When the switch 835 is switched on, a current of a filtered signal isinput through the filtering output terminal 521, and then flows throughthe switch 835, the inductor 836, and the driving output terminals 531and 532, and then flows out from the filtering output terminal 522.During this flowing of current, the current through the inductor 836 andthe voltage of the capacitor 837 both increase with time, so theinductor 836 and the capacitor 837 are in a state of storing energy. Onthe other hand, when the switch 835 is switched off, the inductor 836 isin a state of releasing energy and thus the current through it decreaseswith time. In this case, the current through the inductor 836 circulatesthrough the driving output terminals 531 and 532, the freewheeling diode834, and back to the inductor 836.

In some embodiments the capacitor 837 is an optional element, so it canbe omitted and is thus depicted as a dotted line in FIG. 9D. When thecapacitor 837 is omitted, no matter whether the switch 835 is turned onor off, the current through the inductor 836 will flow through thedriving output terminals 531 and 532 to drive the LED module to continueemitting light. It should be noted that, according to some embodimentsthat utilize the non-isolating driving circuit for performing powerconversion, which means there is no transformer in the driving circuit,the switch 835 is capable of being controlled by detecting the magnitudeof the current flowing through the switch 835 (e.g., the currentdetection signal S535). In some embodiments where the isolating drivingcircuit is utilized for performing power conversion, due to the LEDmodule and the controller being isolated by a transformer, the magnitudeof the current flowing through the switch 835 cannot be used as areference for controlling the switch 835.

As described above, because the controller 833 included in the drivingcircuit 830 is configured for controlling when to turn a switch 835 on(in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531,the driving circuit 830 can maintain a stable current flow through theLED module. Therefore, the color temperature may not change with thecurrent for some LED modules, such as white, red, blue, or green LEDmodules. For example, an LED can retain the same color temperature underdifferent illumination conditions. In some embodiments, because theinductor 836 acting as the energy-storing circuit releases the storedpower when the switch 835 cuts off, the voltage/current flowing throughthe LED module remains above a predetermined voltage/current level sothat the LED module may continue to emit light maintaining the samecolor temperature. In this way, when the switch 835 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theproblem of flickering in the LED module can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

FIG. 9E is a schematic diagram of the driving circuit according to anexemplary embodiment of the present disclosure. Referring to FIG. 9E, adriving circuit 930 in this embodiment comprises a buck DC-to-DCconverter circuit having a controller 933 and a conversion circuit. Theconversion circuit includes an inductor 936, a diode 934 for“freewheeling” of current, a capacitor 937, and a switch 935. Thedriving circuit 930 is coupled to the filtering output terminals 521 and522 to receive and then convert a filtered signal into a lamp drivingsignal for driving an LED module connected between the driving outputterminals 531 and 532.

The inductor 936 has an end connected to the filtering output terminal521 and the driving output terminal 532, and another end connected to afirst end of the switch 935. The switch 935 has a second end connectedto the filtering output terminal 522, and a control terminal connectedto controller 933 to receive a control signal from controller 933 forcontrolling current conduction or cutoff of the switch 935. Thefreewheeling diode 934 has an anode coupled to a node connecting theinductor 936 and the switch 935, and a cathode coupled to the drivingoutput terminal 531. The capacitor 937 is coupled to the driving outputterminals 531 and 532 to stabilize the driving of the LED module coupledbetween the driving output terminals 531 and 532.

The controller 933 is configured for controlling when to turn the switch935 on (in a conducting state) or off (in a cutoff state) according to acurrent detection signal S531 and/or a current detection signal S535.When the switch 935 is turned on, a current is input through thefiltering output terminal 521, and then flows through the inductor 936and the switch 935, and then flows out from the filtering outputterminal 522. During this flowing of current, the current through theinductor 936 increases with time, so the inductor 936 is in a state ofstoring energy; but the voltage of the capacitor 937 decreases withtime, so the capacitor 937 is in a state of releasing energy to keep theLED module continuing to emit light. On the other hand, when the switch935 is turned off, the inductor 936 is in a state of releasing energyand its current decreases with time. In this case, the current throughthe inductor 936 circulates through the freewheeling diode 934, thedriving output terminals 531 and 532, and back to the inductor 936.During this circulation, the capacitor 937 is in a state of storingenergy and its voltage increases with time.

In some embodiments the capacitor 937 is an optional element, so it canbe omitted and is thus depicted as a dotted line in FIG. 10D. When thecapacitor 937 is omitted and the switch 935 is turned on, the currentthrough the inductor 936 doesn't flow through the driving outputterminals 531 and 532, thereby making the LED module not emit light. Onthe other hand, when the switch 935 is turned off, the current throughthe inductor 936 flows through the freewheeling diode 934 and then theLED module to make the LED module emit light. Therefore, by controllingthe time that the LED module emits light, and the magnitude of currentthrough the LED module, the average luminance of the LED module can bestabilized to be above a defined value, thus also achieving the effectof emitting a steady light. It should be noted that, according to someembodiments that utilize the non-isolating driving circuit forperforming power conversion, which means there is no transformer in thedriving circuit, the switch 935 is capable of being controlled bydetecting the magnitude of the current flowing through the switch 935(e.g., the current detection signal S535). In some embodiments where theisolating driving circuit is utilized for performing power conversion,due to the LED module and the controller being isolated by atransformer, the magnitude of the current flowing through the switch 935cannot be used as a reference for controlling the switch 935.

As described above, because the controller 933 included in the drivingcircuit 930 is configured for controlling when to turn a switch 935 on(in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531,the driving circuit 930 can maintain a stable current flow through theLED module. Therefore, the color temperature may not change with thecurrent for some LED modules, such as white, red, blue, or green LEDmodules. For example, an LED can retain the same color temperature underdifferent illumination conditions. In some embodiments, because theinductor 936 acting as the energy-storing circuit releases the storedpower when the switch 935 cuts off, the voltage/current flowing throughthe LED module remains above a predetermined voltage/current level sothat the LED module may continue to emit light maintaining the samecolor temperature. In this way, when the switch 935 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theproblem of flickering in the LED module can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

With reference back to FIGS. 3A and 3B, a short circuit board 253includes a first short circuit substrate and a second short circuitsubstrate respectively connected to two terminal portions of a longcircuit sheet 251, and electronic components of the power supply moduleare respectively disposed on the first short circuit substrate and thesecond short circuit substrate, according to some embodiments of thepresent disclosure. In some embodiments, the first short circuitsubstrate and the second short circuit substrate may have roughly thesame length, or different lengths. In general, the first short circuitsubstrate (i.e. the right circuit substrate of short circuit board 253in FIG. 3A and the left circuit substrate of short circuit board 253 inFIG. 3B) has a length that is about 30%-80% of the length of the secondshort circuit substrate (i.e. the left circuit substrate of shortcircuit board 253 in FIG. 3A and the right circuit substrate of shortcircuit board 253 in FIG. 3B). In some embodiments the length of thefirst short circuit substrate is about ⅓-⅔ of the length of the secondshort circuit substrate. In an exemplary embodiment, the length of thefirst short circuit substrate may be about half the length of the secondshort circuit substrate. The length of the second short circuitsubstrate may be, in some embodiments in the range of about 15 mm toabout 65 mm, depending on actual application occasions. In certainembodiments, the first short circuit substrate is disposed in an end capat an end of the LED tube lamp, and the second short circuit substrateis disposed in another end cap at the opposite end of the LED tube lamp.

In some embodiments, capacitors of the driving circuit, such as thecapacitors 637, 737, 837, and 937 in FIGS. 9B-9E, in practical use mayinclude two or more capacitors connected in parallel. Some or allcapacitors of the driving circuit in the power supply module may bearranged on the first short circuit substrate of short circuit board253, while other components such as the rectifying circuit, filteringcircuit, inductor(s) of the driving circuit, controller(s), switch(es),diodes, etc. are arranged on the second short circuit substrate of shortcircuit board 253. Since the inductors, controllers, switches, etc. areelectronic components with higher temperature, arranging some or allcapacitors on a circuit substrate separate or away from the circuitsubstrate(s) of high-temperature components helps prevent the workinglife of capacitors (especially electrolytic capacitors) from beingnegatively affected by the high-temperature components, thus improvingthe reliability of the capacitors. Further, the physical separationbetween the capacitors and both the rectifying circuit and filteringcircuit also contributes to reducing the problem of EMI.

In some embodiments, components of the driving circuit (such as 1530)that are liable to have relatively higher temperature or overheat aredisposed at one end of the LED tube lamp, or a first end of the LED tubelamp, and are disposed for example in an end cap at the first end; andthe rest of components of the driving circuit are disposed at the otherend of the LED tube lamp, or a second end of the LED tube lamp. In thiscase, for an LED lamp system of a plurality of LED lamp tubes, theplurality of LED lamp tubes may be connected in series wherein the firstend of each of the LED lamp tubes is connected to the second end of oneof the other LED lamp tubes, so that components of the LED lamp systemthat are liable to have relatively higher temperature and disposed atthe first end of each of the plurality of LED lamp tubes are evenlydistributed along the connected LED lamp tubes, as the components arespaced apart by at least the length of each LED lamp tube. Therefore,the drawback of concentrating the components that are liable to haverelatively higher temperature at a specific position along the connectedLED lamp tubes, or concentrating heat generated by the components, isavoided by this way of even distribution, and thus the overall lightingefficiency of the LED lamp system is not negatively affected by thisdrawback.

In certain exemplary embodiments, the conversion efficiency of thedriving circuits is above 80%. In some embodiments, the conversionefficiency of the driving circuits is above 90%. In still otherembodiments, the conversion efficiency of the driving circuits is above92%. In some embodiments, the illumination efficiency of the LED lampsis above 120 lm/W. In some embodiments, the illumination efficiency ofthe LED lamps is above 160 lm/W. In some embodiments, the illuminationefficiency including the combination of the driving circuits and the LEDmodules is above 120 lm/W*90%=108 lm/W. In some embodiments, theillumination efficiency including the combination of the drivingcircuits and the LED modules is above 160 lm/W*92%=147.21 lm/W.

In some embodiments, the transmittance of the diffusion film in the LEDtube lamp is above 85%. As a result, in certain embodiments, theillumination efficiency of the LED lamps is above 108 lm/W*85%=91.8lm/W. In some embodiments, the illumination efficiency of the LED lampsis above 147.21 lm/W*85%=125.12 lm/W.

FIG. 11A is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment of the present disclosure. Comparedto that shown in FIG. 5A, the power supply module 5 of the presentembodiment comprises a rectifying circuit 510, a filtering circuit 520,and a driving circuit 1530, and further comprises an over voltageprotection (OVP) circuit 1570. In this embodiment, a driving circuit 530and an LED module 50 compose the LED lighting module 530. The OVPcircuit 1570 is coupled to the filtering output terminals 521 and 522for detecting the filtered signal. The OVP circuit 1570 clamps the logiclevel of the filtered signal or controls the driving circuit 530 toreduce the magnitude of the driving current (ILED) or to stop outputtingthe driving current when determining the logic level thereof higher thana defined OVP value. Hence, the OVP circuit 1570 protects the LEDlighting module 530 from damage due to an OVP condition.

FIG. 11B is a block diagram of a power supply module in an LED tube lamp500 according to an exemplary embodiment of the present disclosure. Thepower supply module 5 in this embodiment of FIG. 11B is similar to thatin the embodiment of FIG. 11A, with a difference that the OVP circuit550 of FIG. 15B is disposed between the driving circuit 530 and the LEDmodule 50, wherein the OVP circuit 550 of FIG. 15B is coupled to firstand second driving output terminals 531 and 532 of the driving circuit530 for detecting a driving signal. The OVP circuit 550 of FIG. 15B isconfigured to clamp the level of the driving signal when determiningthat the level is higher than a defined OVP value. Hence, the OVPcircuit 550 protects the LED module 50 of FIG. 15B from damages due toan OVP condition.

FIG. 11C is a schematic diagram of an overvoltage protection (OVP)circuit according to an exemplary embodiment. An OVP circuit 650comprises a voltage clamping diode 652, such as zener diode, coupled tothe filtering output terminals 521 and 522 (as shown in FIG. 11A), orcoupled to the driving output terminals 531 and 532 (as shown in FIG.11B). Taking its connection as shown in FIG. 11A as an example, thevoltage clamping diode 652 is conducted to clamp a voltage difference ata breakdown voltage when the voltage difference of the filtering outputterminals 521 and 522 (i.e., the logic level of the filtered signal)reaches the breakdown voltage. In some embodiments, the breakdownvoltage may be in a range of about 40 V to about 100 V. In certainembodiments, the breakdown voltage may be in a range of about 55 V toabout 75V.

FIG. 11D is a block diagram of an overvoltage protection circuitaccording to an exemplary embodiment. Referring to FIG. 11D, theovervoltage protection circuit 750 includes a voltage sampling circuit751 and an enabling circuit 752, in which the voltage sampling circuit751 is coupled to filtering output terminals 521 and 522 in order toreceive the filtered signal. The enabling circuit 752 is coupled to anoutput terminal of the voltage sampling circuit 751, and has an outputterminal coupled to a controller 533 of a driving circuit. The voltagesampling circuit 751 is configured to sample the filtered signal inorder to produce a voltage detection signal for the enabling circuit752. The voltage detection signal may comprise, e.g., a voltage sampledfrom the filtered signal. Therefore, the enabling circuit 752 candetermine whether to activate overvoltage protection, according to thevoltage detection signal, to control the state of operation of thecontroller 533 accordingly.

In some embodiments, the overvoltage protection circuit 750 furtherincludes a delaying circuit 753 coupled to the voltage sampling circuit751 and the enabling circuit 752 and configured for affecting thevoltage detection signal provided by the voltage sampling circuit 751 tothe enabling circuit 752, in order to avoid an incidence in which underspecific application environments a starting but excessive voltagereceived by the LED tube lamp causes a misoperation or wrong operationof the enabling circuit 752 in response to the voltage detection signal.The way that the delaying circuit affects the voltage detection signalmay, for example, be implemented by reducing the rising speed of thelevel of the voltage detection signal or supressing instantaneous changein the voltage detection signal, in order to prevent the sudden jump ofthe voltage detection signal from immediately causing the enablingcircuit 752 to activate or enable overvoltage protection.

For instance, under the situation in which an LED tube lamp is used orsupplied by an instant-start ballast, upon an electrical power supplybeing connected or applied to the LED tube lamp, the LED tube lampreceives an instantaneously high voltage, which may cause misoperationor wrong operation of the enabling circuit 752. If the LED tube lamp isconfigured to include a delaying circuit 753, the instantaneously highvoltage provided by the instant-start ballast applied to the voltagesampling circuit 751 will be suppressed by the delaying circuit 753 andwill not be directly reflected in the voltage detection signal, so as toprevent misoperation or wrong operation of the enabling circuit 752.From another perspective, the delaying circuit 753 delays transmissionof the voltage detection signal output by the voltage sampling circuit751 and then causes transmission of the delayed voltage detection signalto the enabling circuit 752. And the following description explains aplurality of circuit structure embodiments of the overvoltage protectioncircuit 750 with reference to FIGS. 11E-11H.

Referring to FIG. 11E, an overvoltage protection circuit 850 includes avoltage sampling circuit 851, an enabling circuit 852, and a delayingcircuit 853. The voltage sampling circuit 851 includes resistors Rg1,Rg2, and Rg3 and a zener diode ZDg1. The resistors Rg1 and Rg2constitute a voltage divider circuit, in which the resistor Rg1 has afirst end coupled to first filtering output terminal 521 and a secondend coupled to a first end of the resistor Rg2, and the resistor Rg2 hasa second end coupled to second filtering output terminal 522, in whichthe second filtering output terminal 522 is, in some embodiments, at thesame voltage level as a ground terminal GND. The zener diode ZDg1 has acathode coupled to the voltage division point (e.g., node) of thevoltage divider circuit, or the second end of the resistor Rg1 and thefirst end of the resistor Rg2, and the zener diode ZDg1 has an anodecoupled to an input terminal of the enabling circuit 852. The resistorRg3 has a first end coupled to the anode of the zener diode ZDg1, andhas a second end coupled to the second filtering output terminal 522. Inoperation of this embodiment of FIG. 11E, a filtered signal between thefirst filtering output terminal 521 and the second filtering outputterminal 522 is voltage-divided by the resistors Rg1 and Rg2 and thenundergoes voltage-stabilization by the resistor Rg3 and the zener diodeZDg1 to be applied to the input terminal of the enabling circuit 852. Asa result, the voltage signal at the first end of the resistor Rg3 can beregarded as the voltage detection signal produced by the voltagesampling circuit 851.

The delaying circuit 853 includes capacitors Cg1 and Cg2. The capacitorCg1 has a first end coupled to the second end of the resistor Rg1, thefirst end of the resistor Rg2, and the cathode of the Zener diode ZDg1,and has a second end coupled to the second filtering output terminal522. The capacitor Cg2 has a first end coupled to the first end of theresistor Rg3 and the anode of the Zener diode ZDg1, and has a second endcoupled to the second filtering output terminal 522. In operation ofthis embodiment of FIG. 11E, an instantaneous change in the voltagedetection signal is suppressed or limited by the capacitors Cg1 and Cg2.

FIG. 11F-11H illustrate embodiments of partial-circuit-structure ofdifferent circuit connections between the enabling circuit 852 and thecontroller 533, respectively. In these embodiments, the controller 533has, for example, a power pin P_VCC, a driving pin P_G, a compensationpin P_COMP, and a current sampling pin P_CS. The controller 533 isconfigured to be activated when the power pin P_VCC receives a drivingvoltage VCC (such as 5 V) meeting its activation requirement(s), and isconfigured to control, through a signal at the driving pin P_G, themagnitude of an output or driving current from the driving circuit.Further, the controller 533 is configured to adjust a pulse width of anoutput lighting control signal, according to the voltage level at thecurrent sampling pin P_CS (representing the magnitude of the drivingcurrent) and the voltage level at the compensation pin P_COMP(representing the magnitude of an input voltage), in order to make orapproximately maintain the output current/output power of the drivingcircuit above a certain value.

From another perspective, in the configuration of the controller 533,any one pin of the controller 533 may be referred to as the power pinP_VCC (which can be known as a first pin) if activation and deactivation(or stopping of operation) of the controller 533 depends on or is inresponse to the voltage at this one pin. Any one pin of the controller533 may be referred to as the compensation pin P_COMP (which can beknown as a second pin) if the duty cycle of the lighting control signaloutput by the controller 533 decreases with decreasing of the voltage atthis one pin (at least during a certain range of the voltage at this onepin). Any one pin of the controller 533 may be referred to as thecurrent sampling pin P_CS (which can be known as a third pin) if theduty cycle of the lighting control signal output by the controller 533decreases with increasing of the voltage at this one pin (at leastduring a certain range of the voltage at this one pin). In someembodiments, the driving pin P_G may be electrically connected to a gateterminal of the transistor or power switch 535 (illustrated above withreference to FIG. 9A) and may act as a pin for providing a lightingcontrol signal, as illustrated by FIGS. 11F-11H but the presentinvention is not limited to such a connection; and in some otherembodiments, the transistor or power switch 535 is integrated with thecontroller 535 and the driving pin P_G corresponds to a drain terminalof the transistor or power switch 535 in the integrated controller 535,wherein such two types of the driving pin P_G may be referred to as afourth pin.

In the embodiments of FIG. 11F-11H, an example is taken that the drivingpin P_G of the controller 533 is coupled to the gate terminal of thetransistor 535, which has a first terminal coupled to a conversioncircuit and has a second terminal coupled to a ground terminal GNDthrough a sampling resistor Rcs.

Referring to FIG. 11F, the transistor Mg1 of the enabling circuit 852has a first terminal coupled to the power pin P_VCC of the controller533 and a second terminal coupled to the ground terminal GND. When theenabling circuit 852 activates overvoltage protection based on thevoltage detection signal, the transistor Mg1 is conducted in response tothe voltage detection signal, causing the voltage at the power pin P_VCCto be pulled from a driving voltage VCC down to a low or ground voltagelevel and thus causing the controller 533 to stop operating or bedeactivated. On the contrary, when the enabling circuit 852 does notactivate overvoltage protection based on the voltage detection signal,the transistor Mg1 is cut off in response to the voltage detectionsignal, causing the voltage at the power pin P_VCC to remain at thedriving voltage VCC and thus causing the controller 533 to be activatedbased on the driving voltage VCC and then output a lighting controlsignal to the transistor or switching circuit 535.

Referring to FIG. 11G, the transistor Mg1 of the enabling circuit 852has a first terminal coupled to the compensation pin P_COMP of thecontroller 533 through a resistor Rg4 and a second terminal coupled to aground terminal GND. When the enabling circuit 852 activates overvoltageprotection based on the voltage detection signal, the transistor Mg1 isconducted in response to the voltage detection signal, causing thevoltage at the compensation pin P_COMP to be pulled down to a specificvoltage level (depending on the set resistance of the resistor Rg4) orto a low or ground voltage level (as when the resistor Rg4 is notpresent) and thus causing the duty cycle of a lighting control signaloutput by the controller 533 to decrease with decreasing of the voltageat the compensation pin P_COMP so as to reduce the output current/outputpower. On the contrary, when the enabling circuit 852 does not activateovervoltage protection based on the voltage detection signal, thetransistor Mg1 is cut off in response to the voltage detection signal,so that the voltage at the compensation pin P_COMP will not be affectedby the enabling circuit, and therefore the controller 533 can adjust theduty cycle of the output lighting control signal according to thedesigned control mechanism of normal operation.

Referring to FIG. 11H, the transistor Mg1 of the enabling circuit 852has a first terminal coupled to receive a driving voltage VCC through aresistor Rg4 and a second terminal coupled to the current sampling pinP_CS of the controller 533 and a first end of the sampling resistor Rcs.When the enabling circuit 852 activates overvoltage protection based onthe voltage detection signal, the transistor Mg1 is conducted inresponse to the voltage detection signal, causing the driving voltageVCC to be divided and then applied or superposed to the current samplingpin P_CS, causing the voltage level at the current sampling pin P_CS toincrease to a specific level (depending on the set resistances of theresistors Rg4 and Rcs) and thus causing the duty cycle of a lightingcontrol signal output by the controller 533 to decrease with increasingof the voltage at the current sampling pin P_CS so as to reduce theoutput current/output power. On the contrary, when the enabling circuit852 does not activate overvoltage protection based on the voltagedetection signal, the transistor Mg1 is cut off in response to thevoltage detection signal, so that the voltage at the current samplingpin P_CS will not be affected by the enabling circuit, and therefore thecontroller 533 can adjust the duty cycle of the output lighting controlsignal according to the designed control mechanism of normal operation.

FIG. 12A is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Compared to that shown in FIG. 5A,the power supply module 5 of FIG. 12A comprises a rectifying circuit510, a filtering circuit 520, and a driving circuit 530, and furthercomprises an auxiliary power module 560. The auxiliary power module 560is coupled between the filtering output terminals 521 and 522. Theauxiliary power module 560 detects the filtered signal in the filteringoutput terminals 521 and 522, and determines whether to provide anauxiliary power to the filtering output terminals 521 and 522 based onthe detected result. When the supply of the filtered signal is stoppedor a logic level (i.e., a voltage) thereof is insufficient, i.e., when adrive voltage for the LED module is below a defined voltage, theauxiliary power module provides auxiliary power to keep the LED module50 continuing to emit light. The defined voltage is determined accordingto an auxiliary power voltage of the auxiliary power module 560.

FIG. 12B is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Compared to that shown in FIG.12A, the auxiliary power module 560 is coupled between the drivingoutput terminals 531 and 532. The auxiliary power module 560 detects thelamp driving signal in the driving output terminals 531 and 532, anddetermines whether to provide an auxiliary power to the driving outputterminals 531 and 532 based on the detected result. When the lampdriving signal is no longer being supplied or a logic level thereof isinsufficient, the auxiliary power module 560 provides the auxiliarypower to keep the LED module 50 continuously lighting.

In an exemplary embodiment of FIG. 12A, an energy storage unit of theauxiliary power module 560 can be implemented by a supercapacitor (e.g.,electric double-layer capacitor, EDLC). In such an embodiment, since thesupercapacitor provides the filtering function which is the same as thefiltering circuit 520, the filtering circuit 520 can be omitted in thisembodiment.

In another exemplary embodiment, the LED module 50 can be driven merelyby the auxiliary power provided by the auxiliary power module 560, andthe external driving signal is merely used for charging the auxiliarypower module 560. Since such an embodiment applies the auxiliary powerprovided by the auxiliary power module 560 as the only power source forthe LED module 50, regardless of whether the external driving signal isprovided by commercial electricity, the external driving signal chargesthe energy storage unit first, and then the energy storage unit is usedfor supplying power to the LED module. Accordingly, the LED tube lampapplying said power architecture may be compatible with the externaldriving signal provided by commercial electricity.

From the perspective of the structure, since the auxiliary power module560 is connected between the outputs of the filtering circuit 520 (i.e.,the first filtering output 521 and the second filtering output 522) orthe outputs of the driving circuit 530 (i.e., the first driving outputterminal 531 and the second driving output terminal 532), the circuitcomponents of the auxiliary power module 560 can be placed, in anexemplary embodiment, in the lamp tube (e.g., the position adjacent tothe driving circuit 530 or LED module 50 and between the two end caps),such that the power transmission loss caused by the long wiring can beavoided. In another exemplary embodiment, the circuit components of theauxiliary power can be placed in at least one of the end caps, such thatthe heat generated by the auxiliary power module 560 when charging anddischarging does not affect operation and illumination of the LEDmodule.

FIG. 12C is a schematic diagram of an auxiliary power module accordingto an embodiment. The auxiliary power module 660 can be applied, forexample, to the configuration of the auxiliary power module 560illustrated in FIG. 12B. The auxiliary power module 660 comprises anenergy storage unit 663 and a voltage detection circuit 664. Theauxiliary power module 660 further comprises an auxiliary power positiveterminal 661 and an auxiliary power negative terminal 662 for beingrespectively coupled to the filtering output terminals 521 and 522 orthe driving output terminals 531 and 532. The voltage detection circuit664 detects a logic level of a signal at the auxiliary power positiveterminal 661 and the auxiliary power negative terminal 662 to determinewhether to release or not to release outward the power of the energystorage unit 663 through the auxiliary power positive terminal 661 andthe auxiliary power negative terminal 662.

In some embodiments, the energy storage unit 663 is a battery or asupercapacitor. When a voltage difference of the auxiliary powerpositive terminal 661 and the auxiliary power negative terminal 662 (thedrive voltage for the LED module) is higher than the auxiliary powervoltage of the energy storage unit 663, the voltage detection circuit664 charges the energy storage unit 663 by the signal in the auxiliarypower positive terminal 661 and the auxiliary power negative terminal662. When the drive voltage is lower than the auxiliary power voltage,the energy storage unit 663 releases the stored energy outward throughthe auxiliary power positive terminal 661 and the auxiliary powernegative terminal 662.

The voltage detection circuit 664 comprises a diode 665, a bipolarjunction transistor (BJT) 666 and a resistor 667, according to someembodiments. A positive end of the diode 665 is coupled to a positiveend of the energy storage unit 663 and a negative end of the diode 665is coupled to the auxiliary power positive terminal 661. The negativeend of the energy storage unit 663 is coupled to the auxiliary powernegative terminal 662. A collector of the BJT 666 is coupled to theauxiliary power positive terminal 661, and an emitter thereof is coupledto the positive end of the energy storage unit 663. One end of theresistor 667 is coupled to the auxiliary power positive terminal 661 andthe other end is coupled to a base of the BJT 666. When the collector ofthe BJT 666 is a cut-in voltage higher than the emitter thereof, theresistor 667 conducts the BJT 666. When the power source provides powerto the LED tube lamp normally, the energy storage unit 663 is charged bythe filtered signal through the filtering output terminals 521 and 522and the conducted BJT 666 or by the lamp driving signal through thedriving output terminals 531 and 532 and the conducted BJT 666 untilthat the collector-emitter voltage of the BJT 666 is lower than or equalto the cut-in voltage. When the filtered signal or the lamp drivingsignal is no longer being supplied or the logic level thereof isinsufficient, the energy storage unit 663 provides power through thediode 665 to keep the LED module 50 continuously lighting.

In some embodiments, the maximum voltage of the charged energy storageunit 663 is at least one cut-in voltage of the BJT 666 lower than thevoltage difference applied between the auxiliary power positive terminal661 and the auxiliary power negative terminal 662. The voltagedifference provided between the auxiliary power positive terminal 661and the auxiliary power negative terminal 662 is a turn-on voltage ofthe diode 665 lower than the voltage of the energy storage unit 663.Hence, when the auxiliary power module 660 provides power, the voltageapplied at the LED module 50 is lower (about the sum of the cut-involtage of the BJT 666 and the turn-on voltage of the diode 665). In theembodiment shown in the FIG. 12B, the brightness of the LED module 50 isreduced when the auxiliary power module supplies power thereto. Thereby,when the auxiliary power module is applied to an emergency lightingsystem or a constant lighting system, the user realizes the main powersupply, such as commercial power, is abnormal and then performsnecessary precautions therefor.

In addition to utilizing the embodiments illustrated in FIG. 12A to FIG.12C in a single tube lamp architecture for emergency power supply, theembodiments also can be utilized in a lamp module including a multi tubelamp. Taking the lamp module having four parallel arranged LED tubelamps as an example, in an exemplary embodiment, one of the LED tubelamps includes the auxiliary power module. When the external drivingsignal is abnormal, the LED tube lamp including the auxiliary powermodule is continuously lighted up and the others LED tube lamps go off.According to the consideration of the uniformity of illumination, theLED tube lamp having the auxiliary power module can be arranged in themiddle position of the lamp module.

In another exemplary embodiment, a plurality of the LED tube lampsrespectively include the auxiliary power module. When the externaldriving signal is abnormal, the LED tube lamps including the auxiliarypower module are continuously lighted up and the other LED tube lamps(if any) go off. In this way, even if the lamp module is operated in anemergency situation, a certain brightness can still be provided for thelamp module. In addition, if there are two LED lamps that have theauxiliary power module, the LED tube lamps having the auxiliary powermodule can be arranged, according to the consideration of the uniformityof illumination, in a staggered way with the LED tube lamps that don'thave the auxiliary power module.

In still another exemplary embodiment, a plurality of the LED tube lampsrespectively include the auxiliary power module. When the externaldriving signal is abnormal, part of the LED tube lamps including theauxiliary power module is first lighted up by the auxiliary power, andthe other part of the LED tube lamps including the auxiliary powermodule is then lighted up by the auxiliary power after a predeterminedperiod. In this way, the lighting time of the lamp module can beextended during the emergency situation by coordinating the auxiliarypower supply sequence of the LED tube lamps.

The embodiment of coordinating the auxiliary power supply sequence ofthe LED tube lamps can be implemented by setting different start-up timefor the auxiliary power module disposed in different tube lamp, or bydisposing a controller in each tube lamp for communicating the operationstate of each auxiliary power module. The present invention is notlimited thereto.

FIG. 12D is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Referring to FIG. 12D, the powersupply module 5 of FIG. 12D includes a rectifying circuit 510, afiltering circuit 520, a driving circuit 530, and an auxiliary powermodule 760, according to one embodiment. Compared to the embodiment ofFIG. 12B, the auxiliary power module 760 of FIG. 12D is connectedbetween the pins 501 and 502 to receive the external driving signal andperform a charge-discharge operation based on the external drivingsignal, according to some embodiments.

In some embodiments, the operation of the auxiliary power module 760 canbe compared to an Off-line uninterruptible power supply (Off-line UPS).Normally, when an AC power source (e.g., the mains electricity, thecommercial electricity or the power grid) supplies the external drivingsignal to the LED tube lamp, the external driving signal is supplied tothe rectifying circuit 510 while charging the auxiliary power module760. Once the AC power source is unstable or abnormal, the auxiliarypower module 760 takes the place of the AC power source to supply powerto the rectifying circuit 510 until the AC power source recovers normalpower supply. As such, the auxiliary power module 760 can operate in abackup manner by the auxiliary power module 760 interceding on behalf ofthe power supply process when the AC power source is unstable orabnormal. Herein, the power supplied by the auxiliary power module 760can be an AC power or a DC power.

In some embodiments, the current path between the AC power source andthe rectifying circuit 510 is cut off when the AC power source isunstable or abnormal. For example, the unstable AC power source mayoriginate from at least one of the voltage variation, the currentvariation, and the frequency variation of the external driving signalexceeding a threshold. The abnormal AC power source may be caused by atleast one of the voltage, the current, and the frequency of the externaldriving signal being lower or higher than a normal operation range.

The auxiliary power module 760 includes an energy storage unit and avoltage detection circuit, according to some embodiments. The voltagedetection circuit detects the external driving signal, and determineswhether the energy storage unit provides the auxiliary power to theinput terminal of the rectifying circuit 510 according to the detectionresult. When the external driving signal stops providing or the ACsignal level of the external driving signal is insufficient, the energystorage unit of the auxiliary power module 760 provides the auxiliarypower, such that the LED module 50 continues to emit light based on theauxiliary power provided by the auxiliary power module 760. In someembodiments, the energy storage unit for providing auxiliary power canbe implemented by an energy storage assembly such as a battery or asupercapacitor. However, the energy storage assembly of the auxiliarypower module 760 are not limited to the above exemplary embodiments andother energy storage assemblies are contemplated.

FIG. 12E illustrates an exemplary configuration of the auxiliary powermodule 760 operating in an Off-line UPS mode according to someembodiments of the present disclosure. Referring to FIG. 12E, theauxiliary power module 760 includes a charging unit 761 and an auxiliarypower supply unit 762. The charging unit 761 has an input terminalcoupled to an external AC power supply 508 and an output terminalcoupled to an input terminal of the auxiliary power supply unit 762. Theauxiliary power module 760 further includes a switching unit 763, havingterminals connected to the external AC power source 508, an outputterminal of the auxiliary power supply unit 762, and an input terminalof the rectifying circuit 510, respectively, according to someembodiments. In operation, depending on the state of power supply by theexternal AC power source 508, the switching unit 763 is configured toselectively conduct a circuit loop passing through the external AC powersupply 508 and the rectifying circuit 510, or conduct a circuit looppassing through the auxiliary power module 760 and the rectifyingcircuit 510. The auxiliary power supply unit 762 has the input terminalcoupled to the output terminal of the charging unit 761 and an outputterminal coupled to a power loop between the external AC power supply508 and the rectifying circuit 510, via the switching unit 763,according to one embodiment. Specifically, when the external AC powersupply 508 operates normally, the power, supplied by the external ACpower supply 508, will be provided to the input terminal of therectifying circuit 510 as an external driving signal Sed via theswitching unit 763, namely, the switching unit 763 is switched to astate that connects the external AC power supply 508 to the rectifyingcircuit 510. Meanwhile, the charging unit 761 charges the auxiliarypower supply unit 762 based on the power supplied by the external ACpower supply 508, but the auxiliary power supply unit 762 does notoutput power to the rectifying circuit 510 because the external drivingsignal Sed is correctly transmitted on the power loop. When the externalAC power supply 508 is unstable or abnormal, the auxiliary power supplyunit 762 starts to supply an auxiliary power, serving as the externaldriving signal Sed, to the rectifying circuit 510 via the switching unit763, namely, the switching unit 763 is switched to a state that connectsthe output terminal of the auxiliary power supply unit 762 to therectifying circuit 510.

FIG. 12F is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Referring to FIG. 12F, the powersupply module 5 of the present embodiment includes a rectifying circuit510, a filtering circuit 520, a driving circuit 530 and an auxiliarypower module 860 of FIG. 12F. Compared to the embodiment illustrated inFIG. 12D, the input terminals Pi1 and Pi2 of the auxiliary power module860 are configured to receive an external driving signal and perform acharge-discharge operation based on the external driving signal, andthen supply an auxiliary power, generated from the output terminals Po1and Po2, to the rectifying circuit 510. From the perspective of thestructure of the LED tube lamp, the input terminals Pi1 and Pi2 or theoutput terminals Po1 and Po2 of the auxiliary power module 860 areconnected to the pins of the LED tube lamp (e.g., 501 and 502 in FIG.12A or 12B). If the pins 501 and 502 of the LED tube lamp are connectedto the input terminals Pi1 and Pi2 of the auxiliary power module 860, itmeans the auxiliary power module 860 is disposed inside the LED tubelamp and receives the external driving signal through the pins 501 and502. On the other hand, if the pins 501 and 502 of the LED tube lamp areconnected to the output terminals Po1 and Po2 of the auxiliary powermodule 860, it means the auxiliary power module 860 is disposed outsidethe LED tube lamp and outputs the auxiliary power to the rectifyingcircuit through the pins 501 and 502. The detail structure of theauxiliary power module will be further described in the followingembodiments.

In some embodiments, the operation of the auxiliary power module 860 canbe similar to an On-line uninterruptible power supply (On-line UPS).Under the On-line UPS operation, the external AC power source would notdirectly supply power to the rectifying circuit 510, but supplies powerthrough the auxiliary power module 860. Therefore, the external AC powersource can be isolated from the LED tube lamp, and the auxiliary powermodule 860 intervenes the whole power supply process, so that the powersupplied to the rectifying circuit 510 is not affected by the unstableor abnormal AC power source.

FIG. 12G illustrates an exemplary configuration of the auxiliary powermodule 860 operating in an On-line UPS mode according to someembodiments of the present invention. Referring to FIG. 12G, theauxiliary power module 860 includes a charging unit 861 and an auxiliarypower supply unit 862. The charging unit 861 has an input terminalcoupled to an external AC power supply 508 and an output terminalcoupled to a first input terminal of the auxiliary power supply unit862. The auxiliary power supply unit 862 further has a second inputterminal coupled to the external AC power supply 508 and an outputterminal coupled to the rectifying circuit 510. Specifically, when theexternal AC power supply 508 operates normally, the auxiliary powersupply unit 862 performs the power conversion based on the powersupplied by the external AC power source 508, and accordingly providesan external driving signal Sed to the rectifying circuit 510. In themeantime, the charging unit 861 charges an energy storage unit of theauxiliary power supply unit 862. When the external AC power source isunstable or abnormal, the auxiliary power supply unit 862 performs thepower conversion based on the power stored in the energy storage unit,and accordingly provides the external driving signal Sed to therectifying circuit 510. It should be noted that the power conversiondescribed herein could be rectification, filtering, boost-conversion,buck-conversion or a reasonable combination of above operations. Thepresent invention is not limited thereto.

In some embodiments, the operation of the auxiliary power module 860 canbe similar to a Line-Interactive UPS. The basic operation of theauxiliary power module 860 under a Line-Interactive UPS mode is similarto the auxiliary power module 760 under the Off-line UPS mode, thedifference between the Line-Interactive UPS mode and the Off-line UPSmode is the auxiliary 860 has a boost and buck compensation circuit andcan monitor the power supply condition of the external AC power sourceat any time. Therefore, the auxiliary power module 860 can correct thepower output to the power supply module of the LED tube lamp when theexternal AC power source is not ideal (e.g., the external driving signalis unstable but the variation does not exceed the threshold value), soas to reduce the frequency of using the battery for power supply.

FIG. 12H illustrates an exemplary configuration of the auxiliary powermodule 860 operating in the Line-Interactive mode according to someembodiments of the present invention. Referring to FIG. 12H, theauxiliary power module 860 includes a charging unit 861, an auxiliarypower supply unit 862 and a switching unit 863. The charging unit 861has an input terminal coupled to an external AC power supply 508. Theswitching unit 863 is coupled between an output terminal of theauxiliary power supply unit 862 and an input terminal of the rectifyingcircuit 510, in which the switching unit 863 may selectively conduct acurrent on a path between the external AC power supply 508 and therectifying circuit 510 or on a path between the auxiliary power supplyunit 862 and the rectifying circuit 510 according to the power supplycondition of the external AC power supply 508. In detail, when theexternal AC power source is normal, the switching unit 863 is switchedto conduct a current on the path between the external AC power supply508 and the rectifying circuit 510 and cut off the path between theauxiliary power supply unit 862 and the rectifying circuit 510. Thus,when the external AC power source is normal, the external AC powersupply 508 provides power, regarded as the external driving signal Sed,to the input terminal of the rectifying circuit 510 via the switchingunit 863. In the meantime, the charging unit 861 charges the auxiliarypower unit 862 based on the external AC power supply 508. When theexternal AC power source is unstable or abnormal, the switching unit 863is switched to conduct a current on the path between the auxiliary powersupply unit 862 and the rectifying circuit 510 and cut off the pathbetween the AC power supply 508 and the rectifying circuit 510. Theauxiliary power supply unit 862 starts to supply power, regarded as theexternal driving signal Sed, to the rectifying circuit 510.

In the embodiments of the auxiliary power module, the auxiliary powerprovided by the auxiliary power supply unit 762/862 can be in either ACor DC. When the auxiliary power is provided in AC, the auxiliary powersupply unit 762/862 includes, for example, an energy storage unit and aDC-to-AC converter. When the auxiliary power is provided in DC, theauxiliary power supply unit 762/862 includes, for example, an energystorage unit and a DC-to-DC converter, or simply includes an energystorage unit; the present invention is not limited thereto and otherenergy storage units are contemplated. In some embodiments, the energystorage unit can be a set of batteries. In some embodiments, theDC-to-DC converter can be a boost converter, a buck converter or abuck-boost converter. The energy storage unit may be e.g. a batterymodule composed of a number of batteries. The DC-to-DC converter may bee.g. of the type of buck, boost, or buck-boost converter. And theauxiliary power module 760/860 further includes a voltage detectioncircuit, not shown in FIGS. 12D to 12H. The voltage detection circuit isconfigured to detect an operating state of the external AC power supply508 and generate a signal, according to the detection result, to controlthe switching unit 763/863 or the auxiliary power supply unit 862, inorder to determine whether the LED tube lamp operates in a normallighting mode (i.e., supplied by the external AC power supply 508) or inan emergency lighting mode (i.e., supplied by the auxiliary power module760/860). In such embodiments, the switching unit 763/863 may beimplemented by a three-terminal switch or two complementary switcheshaving a complementary relation. When using the complementary switches,one of the complementary switches may be serially connected on the powerloop of the external AC power supply 508 and the other one of thecomplementary switches may be serially connected on the power loop ofthe auxiliary power module 760/860, wherein the two complementaryswitches are controlled in a way that when one switch is conducting theother switch is cut off.

In an exemplary embodiment, the switching unit 763/863 is implemented bya relay. The relay operates similar to a two-mode switch. In function,when the LED tube lamp is operating in a normal lighting mode (i.e.,electricity provided from the external AC power supply 508 is normallyinput to the LED tube lamp as an external driving signal), the relay ispulled in so that the power supply module of the LED tube lamp is notelectrically connected to the auxiliary power module 760/860. On theother hand, when the AC power line is abnormal and fails to providepower as the external AC power supply 508, magnetic force in the relaydisappears so that the relay is released to a default position, causingthe power supply module of the LED tube lamp to be electricallyconnected to the auxiliary power module 760/860 through the relay, thususing the auxiliary power module 760/860 as a power source.

According to some embodiments, from the perspective of the entirelighting system, when used in the normal lighting occasion, theauxiliary power module 760/860 is not active to provide power, and theLED module 50 is supplied by the AC power line, which also may chargethe battery module of the auxiliary power module 760/860. On the otherhand, when used in the emergency lighting occasion, voltage of thebattery module is increased by the boost-type DC-to-DC converter to alevel required by the LED module 50 to operate in order to emit light.In some embodiments, the voltage level after the boosting is usually orcommonly about 4 to 10 times that of the battery module before theboosting, and is in some embodiments 4 to 6 times that of the batterymodule before the boosting. In this embodiment, the voltage levelrequired by the LED module 50 to operate is be in the range 40 to 80 V,and is preferably in the range 55 to 75 V. In one disclosed embodimentherein, 60 V is chosen as the voltage level, but the voltage level maybe other values in other embodiments.

In one embodiment, the battery module includes or is implemented by asingle cylindrical battery or cell packaged in a metallic shell toreduce the risk of leakage of electrolyte from the battery. In oneembodiment, the battery can be modularized as a packaged battery moduleincluding for example two battery cells connected in series, in which aplurality of the battery module can be electrically connected insequence (e.g., in series or in parallel) and disposed inside the lampfixture so as to reduce the complexity of maintenance. For instance,when one or part of the battery modules are damaged or bad, each damagedbattery module can be easily replaced without the need to replace all ofthe plurality of battery modules. In some embodiments of the presentdisclosure, the battery module may be designed to have a cylindricalshape whose internal diameter is slightly longer than the outer diameterof each of its battery cells, for the battery module to accommodate itsbattery cells in sequence and to form a positive electrode and anegative electrode at two terminals of the battery module. In someembodiments, the voltage of the battery modules electrically connectedin series may be designed to be lower than e.g. 36V. In someembodiments, the battery module is designed to have a cuboid shape whosewidth is slightly longer than the outer diameter of each of its batterycells, for its battery cells to be securely engaged in the batterymodule, wherein the battery module may be designed to have a snap-fitstructure or other structure for easily plugging-in and pulling-out ofits battery cells. However, it is understood by those skilled in the artthat in some other embodiments the battery module may have other shapesbesides cuboid, such as rectangular.

In one embodiment, the charging unit 761/861 is e.g. a batterymanagement system (BMS), which is used to manage the battery module,mainly for intelligent management and maintenance of the battery modulein order to prevent over-charging and over-discharging of the batterycells of the battery module. The BMS prolongs the usage lifetime of thebattery cells, and to monitor states of the battery cells.

The BMS may be designed to have a port capable of connecting an externalmodule or circuit, for reading or accessing information/data related tothe battery cells through the port during periodical examinations of thebattery module. If an abnormal condition of the battery module isdetected, the abnormal battery module can be replaced.

In other embodiments, the number of battery cells that a battery modulecan hold may be more than 2, such as 3, 4, 10, 20, 30, or anothernumber, and the battery cells in a battery module may be designed to beconnected in series, or some of which are connected in series and someof which are connected in parallel, depending on actual applicationoccasions. In some embodiments where lithium battery cells are used, therated voltage of a single lithium battery cell is about 3.7V. In someembodiments the number of battery cells of a battery module can bereduced to keep the voltage of the battery unit to be below about 36V.

The relay used in these embodiments is e.g. a magnetic relay mainlyincluding an iron core, coil(s), an armature, and contacts or a reed.The operations principle of the relay may be: when power is applied totwo ends of the coil, a current is passed through the coil to produceelectromagnetic force, activating the armature to overcome a forceprovided by a spring and be attracted to the iron core. The movement ofthe armature brings one of the contacts to connect to a fixednormally-open contact of the contacts. During a power outage or when thecurrent is switched off, the electromagnetic force disappears and so thearmature is returned by a reaction force provided by the spring to itsrelaxed position, bringing the moving contact to connect to a fixednormally-closed contact of the contacts. By these different movements ofswitching, current conduction and cutoff through the relay can beachieved. A normally-open contact and a normally-closed contact of arelay may be defined such that a fixed contact which is in an open statewhen the coil of the relay is de-energized is called a normally-opencontact, and a fixed contact which is in a closed state when the coil ofthe relay is de-energized is called a normally-closed contact.

In an exemplary embodiment, the brightness of the LED module supplied bythe external driving signal is different from the brightness of the LEDmodule supplied by the auxiliary power module. Therefore, a user mayfind the external power is abnormal when observing that the brightnessof LED module changed, and thus the user can eliminate the problem assoon as possible. In this manner, the operation of the auxiliary powermodule 760 can be considered as an indication of whether the externaldriving signal is normally provided, wherein when the external drivingsignal becomes abnormal, the auxiliary power module 760 provides theauxiliary power having the output power different from that of thenormal external driving signal. For example, in some embodiments, theluminance of the LED module is 1600 to 2000 lm when being lighted up bythe external driving signal; and the luminance of the LED module is 200to 250 lm when being lighted up by the auxiliary power. From theperspective of the auxiliary power module 760, in order to let theluminance of the LED module reach 200-250 lm, the output power of theauxiliary power module 760 is, for example, 1 watt to 5 watts, but thepresent invention is not limited thereto. In addition, the electricalcapacity of the energy storage unit in the auxiliary power module 760may be, for example, 1.5 to 7.5 Wh (watt-hour) or above, so that the LEDmodule can be lighted up for 90 minutes under 200-250 lm based on theauxiliary power. However, the present invention is not limited thereto.

FIG. 12I illustrates a schematic structure of an auxiliary power moduledisposed in an LED tube lamp according to an exemplary embodiment. Inone embodiment, in addition, or as an alternative, the auxiliary powermodule 760/860 is disposed in the lamp tube 1. In another embodiment,the auxiliary power module 760/860 is disposed in the end cap 3. Inorder to make the description more clear, the auxiliary power module 760is chosen as a representative of the auxiliary power modules 760 and 860in the following paragraph, and only 760 is indicated in the figures.When the auxiliary power module 760 is disposed in an end cap 3, in someembodiments the auxiliary power module 760 connects to the correspondingpins 501 and 502 via internal wiring of the end cap 3, so as to receivethe external driving signal provided to the pins 501 and 502. Comparedto the structure of disposing the auxiliary power module into the lamptube 1, the auxiliary power module 760 can be disposed far apart fromthe LED module since the auxiliary power module 760 is disposed in theend cap 3 which is connected to the respective end of the lamp tube 1.Therefore, the operation and illumination of the LED module won't beaffected by heat generated by the charging or discharging of theauxiliary power module 760. In some embodiments, the auxiliary powermodule 760 and the power supply module of the LED tube lamp are disposedin the same end cap, and in other embodiments the auxiliary power module760 and the power supply module are disposed in different end caps onthe respective ends of the lamp tube. In those embodiments where theauxiliary power module 760 and the power supply module of the LED tubelamp are respectively disposed in the different end caps, each modulemay have more area for circuit layout.

Referring to FIG. 12J, the auxiliary power module 760 is disposed in alamp socket 1_LH of the LED tube lamp, according to one embodiment. Inone embodiment, the lamp socket 1_LH includes a base 101_LH and aconnecting socket 102_LH. The base 101_LH has power line disposed insideand is adapted to lock/attach to a fixed object such as a wall or aceiling. The connecting socket 102_LH has slot corresponding to the pin(e.g., the pins 501 and 502) on the LED tube lamp, in which the slot iselectrically connected to the corresponding power line. In theembodiment shown in FIG. 12J, the connecting socket 102_LH and the base101_LH are formed of one piece. In another embodiment, the connectingsocket 102_LH is removably disposed on the base 101_LH. It is understoodby those skilled in the art that the particular lamp socket 1_LHarrangement is not limited one of these embodiments but that otherarrangements are also contemplated.

In some embodiments when the LED tube lamp is installed in the lampsocket 1_LH, the pins on both end caps 3 are respectively inserted intothe slot of the corresponding connecting socket 102_LH, and thus thepower line can be connected to the LED tube lamp for providing theexternal driving signal to the corresponding pins of the LED tube lamp.Taking the configuration of the left end cap 3 as an example, when thepins 501 and 502 are inserted into the slots of the connecting socket102_LH, the auxiliary power module 760 is electrically connected to thepins 501 and 502 via the slots, so as to implement the connectionconfiguration shown in FIG. 12D.

Compared to the embodiment of disposing the auxiliary power module 760in the end cap 3, the connecting socket 102_LH and the auxiliary powermodule 760 can be integrated as a module since the connecting socket canbe designed as a removable configuration in an exemplary embodiment.Under such configuration, when the auxiliary power module 760 has afault or the service life of the energy storage unit in the auxiliarypower module 760 has run out, a new auxiliary power module can bereplaced for use by replacing the modularized connecting socket 102_LH,instead of replacing the entire LED tube lamp. Thus, in addition toreducing the thermal effect of the auxiliary power module, themodularized design of the auxiliary power module has the added advantageof making the replacement of the auxiliary power module easier.Therefore, the durability as well as the cost savings of the LED tubelamp is evident since it is no longer necessary to replace the entireLED tube lamp when a problem occurs to the auxiliary power module. Inaddition, in some embodiments, the auxiliary power module 760 isdisposed inside the base 101_LH. In other embodiments, the auxiliarypower module 760 is disposed outside the base 101_LH. It is understoodthat the particularly arrangement of the auxiliary power module 760 withrespect to the base 101_LH is not limited to what is described in thepresent disclosure but that other arrangements are also contemplated.

In summary, the structural configuration of the auxiliary power module760 can be divided into the following two types: (1) the auxiliary powermodule is integrated into the LED tube lamp; and (2) the auxiliary powermodule 760 is disposed independent from the LED tube lamp. Under theconfiguration of disposing the auxiliary power module 760 independentfrom the LED tube lamp, if the auxiliary power module 760 operates inthe Off-line UPS mode, the auxiliary power module 760 and the externalAC power source can provide power, through different pins or throughsharing at least one pin, to the LED tube lamp. On the other hand, ifthe auxiliary power module 760 operates in the On-line UPS mode or theLine-Interactive mode, the external AC power source provides powerthrough the auxiliary power module 760 rather than directly to the pinsof the LED tube lamp. The detailed configuration of disposing theauxiliary power module independent from the LED tube lamp (hereinafterthe independent auxiliary power module) is further described below.

It should be noted that the combination of the lamp and the lamp socketcould be regarded as a light fixture, a lamp fixture, a light fitting orluminaries. For example, the lamp socket in the disclosure can beregarded as a part of the light fixture for securing, attaching orappending as to a house, apartment building, etc, and for holding andproviding power to the lamps. In addition, the connecting sockets 102_LHcan be described as tombstone sockets of the light fixture.

FIG. 12K is a block diagram of an LED lighting system according to anexemplary embodiment. Referring to FIG. 12K, the LED lighting systemincludes an LED tube lamp 600 and an auxiliary power module 960. The LEDtube lamp 600 includes rectifying circuits 510 and 540, a filteringcircuit 520, a driving circuit 530 and an LED module (not shown). Therectifying circuits 510 and 540 can be respectively implemented by thefull-wave rectifier 610 illustrated in FIG. 7A or the half-waverectifier 710 as shown in FIG. 7B, in which two input terminals of therectifying circuit 510 are coupled to the pins 501 and 502 and two inputterminals of the rectifying circuit 540 are coupled to the pins 503 and504.

In the embodiment shown in FIG. 12K, the LED tube lamp 600 is configuredas a dual-end power supply structure for example. The external AC powersupply 508 is coupled to the pins 501 and 502 on the respective end capsof the LED tube lamp 600, and the auxiliary power module 960 is coupledto the pins 503 and 504 on the respective end caps of the LED tube lamp600.

In this embodiment, the external AC power supply 508 and the auxiliarypower module 960 provide power to the LED tube lamp 600 throughdifferent pairs of the pins. Although the present embodiment isillustrated in dual-end power supply structure for example, the presentinvention is not limited thereto. In another embodiment, the external ACpower supply 508 can provide power through the pins 501 and 503 on theend cap at one side of the lamp tube (i.e., the single-end power supplystructure), and the auxiliary power module 960 can provide power throughthe pins 502 and 504 on the end cap at the other side of the lamp tube.Accordingly, no matter whether the LED tube lamp 600 is configured inthe single-end or the dual-end power supply structure, the unused pinsof the original LED tube lamp (e.g., 503 and 504 illustrated in FIG.12K) can be the interface for receiving the auxiliary power, so that theemergency lighting function can be integrated in the LED tube lamp 600.

FIG. 12L is a block diagram of an LED lighting system according toanother exemplary embodiment. Referring to FIG. 12L, the LED lightingsystem includes an LED tube lamp 700 and an auxiliary power module 1060.The LED tube lamp 700 includes a rectifying circuit 510, a filteringcircuit 520, a driving circuit 530 and an LED module (not shown). Therectifying circuit 510 can be implemented by the rectifying circuit 910having three bridge arms as shown in FIGS. 7D to 7F, in which therectifying circuit 510 has a first signal input terminal P1 coupled tothe pin 501, a second signal input terminal P2 coupled to the pin 502and the auxiliary power module 1060 and a third input terminal P3coupled to the auxiliary power module 1060.

In the present embodiment, the LED tube lamp 700 is configured as adual-end power supply structure for example. The external AC powersupply 508 is coupled to the pins 501 and 502 on the respective end capsof the LED tube lamp 500. The difference between the present embodimentshown in FIG. 12L and the embodiment illustrated in FIG. 12K is thatbesides being coupled to the pin 502, the auxiliary power module 1060further shares the pin 503 with the external AC power supply 508. Underthe configuration of FIG. 12L, the external AC power supply 508 providespower to the signal input terminals P1 and P3 of the rectifying circuit510 through the pins 501 and 503, and the auxiliary power module 1060provides power to the signal input terminals P2 and P3 of the rectifyingcircuit 510 through the pins 502 and 503. In detail, if the leadsconnected to the pins 501 and 503 are respectively configured as a livewire (denoted by “(L)”) and a neutral wire (denoted by “(N)”), theauxiliary power module 1060 shares the lead (N) with the external ACpower supply 508 and has a lead for transmitting power as a live wiredistinct from the external AC power supply 508. In this manner, thesignal input terminal P3 is a common terminal between the external ACpower supply 508 and the auxiliary power module 1060.

In operation, when the external AC power source normally operates, therectifying circuit 510 performs the full-wave rectification by thebridge arms corresponding to the signal input terminals P1 and P2, so asto provide power to the LED module 50 based on the external AC powersupply 508. However, when the external AC power source is unstable orabnormal, the rectifying circuit 510 performs the full-waverectification by the bridge arms corresponding to the signal inputterminals P2 and P3, so as to provide power to the LED module 50 basedon the auxiliary power provided by the auxiliary power module 1060.

In addition, since the LED tube lamp receives the auxiliary powerprovided by the auxiliary power module 1060 through sharing the pin 502,an unused pin (e.g., pin 504) can be used as a signal input interface ofother control functions. These other control functions can be a dimmingfunction, a communication function or a sensing function, though thepresent invention is not limited thereto. The embodiment of integratingthe dimming function through the unused pin 504 is further describedbelow.

FIG. 12M is a block diagram of an LED lighting system according to stillanother exemplary embodiment. Referring to FIG. 12M, the LED lightingsystem includes an LED tube lamp 800 and an auxiliary power module 1060.The LED tube lamp 800 includes a rectifying circuit 510, a filteringcircuit 520, a driving circuit 530 and an LED module 50. Theconfiguration of the present embodiment is similar to the embodimentillustrated in FIG. 12L. The difference between the embodiments of FIGS.12M and 12L is, as shown in FIG. 12M, the pin 504 of the LED tube lamp800 is further coupled to a dimming control circuit 570, in which thedimming control circuit 570 is coupled to the driving circuit 530through the pin 504, so that the driving circuit 530 can adjust themagnitude of the driving current, supplied to the LED module 50,according to a dimming signal received from the dimming control circuit570. Therefore, the brightness and/or the color temperature of the LEDmodule 50 can be varied according to the dimming signal.

For example, the dimming control circuit 570 can be implemented by acircuit including a variable impedance component (e.g., a variableresistor, a variable capacitor or a variable inductor) and a signalconversion circuit. The impedance of the variable impedance componentcan be tuned by a user, so that the dimming control circuit 570generates the dimming signal having signal level corresponding to theimpedance. After converting the signal formation (e.g., signal level,frequency or phase) of the dimming signal to conform the signalformation of the driving circuit 530, the converted dimming signal istransmitted to the driving circuit 530, so that the driving circuit 530adjusts the magnitude of the driving current based on the converteddimming signal. In some embodiments, the brightness of the LED module 50can be adjusted by tuning the frequency or the reference level of thelamp driving signal. In some embodiments, the color temperature of theLED module 50 can be adjusted by tuning the brightness of the red LEDunits.

It should be noted that, by utilizing the structural configurations asshown in FIGS. 12I and 12J, the auxiliary power module 960/1060 canobtain the similar benefits and advantages described in the embodimentsof FIGS. 12I and 12J. In addition, although the dummy pins (i.e., thepins not used for receiving the external driving signal, such as thepins 503 and 504 illustrated in FIGS. 12K to 12M) are used for receivingthe auxiliary power and the dimming signal, the invention is not limitedthereto. In some embodiments, the dummy pins can be used for otherfunctions, such as for receiving a remote control signal or outputting asensing signal, by correspondingly disposing circuits connected to thedummy pins for performing the functions. For example, the dummy pins inthe LED tube lamp can be configured to a signal input/output interfacefor performing certain functions.

In a configuration of a light fixture having multi LED tube lamps, whichis similar to the embodiments described in FIG. 12A to FIG. 12C, theauxiliary power module can be disposed in one tube lamp, or in pluraltube lamps, in which the multi tube lamps architectures based on theconsideration of the uniformity of illumination are adapted to thepresent embodiment as well. The difference between the embodiment havingmulti tube lamps and the embodiments illustrated in FIG. 12A to FIG. 12Qis that the auxiliary power module disposed in one of the tube lamps maysupply power to the other tube lamps.

It should be noted that, although the description of the lamp modulehaving multi tube lamps herein is taking the four parallel LED tubelamps as an example, those skilled in the art should understand, basedon the description mentioned above, how to implement an auxiliary powersupply by selecting and disposing the suitable energy storage unit.Therefore, any embodiments illustrated in which the auxiliary powermodule 760/860 provides auxiliary power to one or plural tube lamps,such that the corresponding LED tube lamp has a specific illuminance inresponse to the auxiliary power, may be implemented according to thedisclosed embodiments.

In another exemplary embodiment, the auxiliary power modules 560, 660,760, 860, 960 and 1060 determine whether to provide the auxiliary powerto the LED tube lamp according to a lighting signal. Specifically, thelighting signal is an indication signal indicating the switching stateof the lamp switch. For example, the signal level of the lighting signalcan be adjusted to a first level (e.g., high logic level) or a secondlevel different from the first level (e.g., low logic level) accordingto the switching of the lamp switch. When a user toggles the lamp switchto an on-position, the lighting signal is adjusted to the first level;and when the user toggles the lamp switch to an off-position, thelighting signal is adjusted to the second level. For example, the lampswitch may be switched to the on-position when the lighting signal is atthe first level and to the off-position when the lighting signal is atthe second level. The generation of the lighting signal can beimplemented by a circuit, as is conventionally known to those ofordinary skill in the art, capable of detecting the switching state ofthe lamp switch.

In still another exemplary embodiment, the auxiliary power module560/660/760/860/960/1060 further includes a lighting determinationcircuit for receiving the lighting signal and determining whether theenergy storage unit provides the auxiliary power to the end of the LEDtube lamp (e.g., to provide the auxiliary power to the LED module)according to the signal level of the lighting signal and the detectionresult of the voltage detection circuit. Specifically, based on thesignal level of the lighting signal and the detection result, there arethree different states as follows: (1) the lighting signal is at thefirst level and the external driving signal is normally provided; (2)the lighting signal is at the first level and the external drivingsignal stops being provided or the AC signal level of the externaldriving signal is insufficient; and (3) the lighting signal is at thesecond level and the external driving signal stops being provided.Herein, state (1) is the situation where a user turns on the lamp switchand the external driving signal is normally provided, state (2) is thesituation where a user turns on the lamp switch however a problem occursto the external power supply, and state (3) is the situation where auser turns off the lamp switch so that the external power supply isstopped.

In the present exemplary embodiment, states (1) and (3) belong to normalstates, which means the external power is normally provided or stops inaccordance with the user's control. Therefore, under states (1) and (3),the auxiliary power module does not provide auxiliary power to the endof the LED tube lamp (e.g., to the LED module). More specifically, thelighting determination circuit controls the energy storage unit not toprovide the auxiliary power to the end of the LED tube lamp according tothe determination result of states (1) and (3). In state (1), theexternal driving signal is directly input to the rectifying circuit 510and charges the energy storage unit. In state (3), the external drivingsignal stops being provided so that the energy unit is not charged bythe external driving signal.

State (2) represents the external power is not provided to the tube lampwhen the user turns on the light, therefore, the lighting determinationcircuit controls the energy storage unit to provide the auxiliary powerto the rear end according to the determination result indicating state(2), so that the LED module 530 emits light based on the auxiliary powerprovided by the energy storage unit.

Accordingly, based on the application of the lighting determinationcircuit, the LED module 530 may have three different luminancevariations. The LED module 530 has a first luminance (e.g., 1600 to 2200lm) when the external power is normally supplied; the LED module 50 hasa second luminance (e.g., 200 to 250 lm) when the external power isabnormal and the power supply is changed to the auxiliary power; and theLED module 50 has a third luminance (e.g., does not light up the LEDmodule) when the user turns off the power on their own such that theexternal power is not provided to the LED tube lamp.

More specifically, in accordance with the embodiment of FIG. 12C, thelighting determination circuit is, for example, a switch circuit (notshown) connected between the auxiliary power positive terminal 661 andthe auxiliary power negative terminal 662 in series. The controlterminal of the switch circuit receives the lighting signal. When thelighting signal is at the first level, the switch circuit is conductedin response to the lighting signal, such that the external drivingsignal charges the energy storage unit 663 via the auxiliary powerpositive terminal 661 and the auxiliary power negative terminal 662 whenthe external driving signal is normally supplied (state (1)), or makesthe energy storage unit 663 discharge to the driving circuit 530 or LEDmodule 50 via the auxiliary power positive terminal 661 and theauxiliary power negative terminal 662 when the external driving signalstops providing or the AC signal level of the external driving signal isinsufficient (state (2)). On the other hand, when the lighting signal isat the second level, the switch circuit is cut off in response to thelighting signal (state (3)). At this time, even though the externaldriving signal stops being provided or the AC signal level isinsufficient, the energy storage unit 663 won't provide the auxiliarypower to the rear end (e.g., to the LED module).

In applications of the above auxiliary power module, the circuit of theauxiliary power supply unit (such as 762 or 862) is designed to be underopen-loop control, i.e. for example the auxiliary power supply unitgenerates the output voltage without referring to a feedback signalindicating a load state. In this case when the load is in anopen-circuit condition, this will cause the output voltage of theauxiliary power module to keep increasing so as to damage the auxiliarypower module. To address this issue, this disclosure presents severalcircuit (block) embodiments of the auxiliary power module havingopen-circuit protection, as shown in FIGS. 12N and 12O.

FIG. 12N is a circuit diagram of the auxiliary power module according toan embodiment. Referring to FIG. 12N, in this embodiment, the auxiliarypower module 1160 includes a charging unit 1161 and an auxiliary powerunit 1162. The auxiliary power unit 1162 includes a transformer, asampling module 1164, a control module 1165, and an energy storage unit1163 for providing a supply voltage Vcc. In the auxiliary power module1160, also with reference to FIG. 12E, the transformer includes aprimary winding L1 and a secondary winding L2. A terminal of thesecondary winding L2 is electrically connected to switching unit 763 andtherefore is electrically connected to an end of the LED tube lamp (orto input terminal(s) of rectifying circuit 510), and the other terminalof the secondary winding L2 is electrically connected to the other endof the LED tube lamp. Sampling module 1164 includes an auxiliary windingL3, which is wound along with the secondary winding L2 at the secondaryside. Voltage of the secondary winding L2 is sampled by the auxiliarywinding L3. If the sampled voltage exceeds a set threshold value, thesampled voltage is fed back to the control module 1165, and then thecontrol module 1165 modulates switching frequency of a switch M1electrically connected to the primary winding L1 based on the sampledvoltage. This way of modulating the switching frequency of switch M1then controls output voltage at the secondary side, thereby realizingopen-circuit protection.

Specifically, the transformer includes a primary side unit and asecondary side unit. The primary side unit includes an energy storageunit 1163, a primary winding L1, and a switch M1. A positive electrodeof the energy storage unit 1163 is electrically connected to a dottedterminal of the primary winding L1, and a negative electrode of theenergy storage unit 1163 is electrically connected to a ground terminal.A non-dotted terminal of the primary winding L1 is electricallyconnected to the drain terminal of the switch M1 (such as a MOSFET). Thegate terminal of the switch M1 is electrically connected to controlmodule 1165, and the source terminal of switch M1 is connected to aground terminal. The secondary side unit includes secondary winding L2,a diode D1, and a capacitor C1. A non-dotted terminal of the secondarywinding L2 is electrically connected to the anode of diode D1, and adotted terminal of secondary winding L2 is electrically connected to anend of the capacitor C1. The cathode of the diode D1 is electricallyconnected to the other end of the capacitor C1. The two ends of thecapacitor C1 can be regarded as auxiliary power supply output terminalsV1 and V2 (corresponding to two terminals of the auxiliary power module960 in FIG. 12K, or two terminals of the auxiliary power module 1060 inFIGS. 12L and 12M).

Sampling module 1164 includes an auxiliary winding L3, a diode D2, acapacitor C2, and a resistor R1. A non-dotted terminal of the auxiliarywinding L3 is electrically connected to the anode of diode D2, and adotted terminal of auxiliary winding L3 is electrically connected to afirst common end connecting the capacitor C2 and the resistor R1. Thecathode of diode D2 is electrically connected to another common end(marked with “A” in FIG. 12N) connecting the capacitor C2 and theresistor R1. And the capacitor C2 and the resistor R1 are electricallyconnected to control module 1165 through the node A.

The control module 1165 includes a controller 1166, a diode D3,capacitors C3, C4 and C5, and resistors R2, R3, and R4. The ground pinGT of the controller 1166 is grounded to the ground terminal GND. Theoutput pin OUT of the controller 1166 is electrically connected to thegate terminal of switch M1. The trigger pin TRIG of the controller 1166is electrically connected to an end (marked with “B”) of the resistorR2. The discharge pin DIS of the controller 1166 is electricallyconnected to the other end of resistor R2. The reset pin RST of thecontroller 1166 is electrically connected to an end of the capacitor C3,which has the other end connected to the ground terminal GND. Theconstant voltage pin CV of the controller 1166 is electrically connectedto an end of the capacitor C4, which has the other end connected to theground terminal GND. The discharge terminal DIS of the controller 1166is coupled to an end of the capacitor C5 through the resistor R2, whichcapacitor C5 has the other end connected to the ground terminal GND. Thepower supply pin VC of the controller 1166 receives supply voltage Vccand is electrically connected to an end of the resistor R3, which hasthe other end electrically connected to the node B. The anode of thediode D3 is electrically connected to the node A, the cathode of diodeD3 is electrically connected to an end of the resistor R4, which has theother end electrically connected to the node B.

What follows here is a description of operations of the circuitembodiment in FIG. 12N. When the auxiliary power module 1160 is in anormal state, the output voltage between output terminals V1 and V2 ofthe auxiliary power module 1160 is low and usually lower than a specificvalue, for example 100 V. In the present embodiment, the output voltagebetween the output terminals V1 and V2 is in the range 60 V to 80 V. Atthis time the voltage, relative to the ground terminal GND, sampled atthe node A of the sampling module 1164 is low such that a small currentis flowing through the resistor R4 and can be ignored. When theauxiliary power module 1160 is in an abnormal state, the output voltagebetween the output terminals V1 and V2 of the auxiliary power module1160 is relatively high, for example over 300 V, and then the voltagesampled at the node A of the sampling module 1164 is relatively highsuch that a relatively large current is flowing through the resistor R4.The relatively large current flowing through the resistor R4 increasesthe discharge time of the capacitor C5, whose charge time is unchanged,and this amounts to adjusting the duty cycle of the switch M1 toincrease the cutoff time. With respect to the output side of thetransformer, the adjusting of the duty cycle causes a smaller outputenergy, and thus the output voltage will not keep increasing, so as toachieve the purpose of open-circuit protection.

In this embodiment, the trigger terminal TRIG of the controller 1166 iselectrically connected to the discharge terminal DIS of the controller1166 through the resistor R2, and the discharge terminal DIS istriggered when the voltage at the node B is in the range (⅓)*Vcc to(⅔)*Vcc (the “*” denoting multiplication). When the auxiliary powermodule 1160 is in the normal state, i.e. its output voltage does notexceed a set threshold value, the voltage sampled at the node A may belower than (⅓)*Vcc. When the auxiliary power module 1160 is in theabnormal state, the voltage sampled at the node A may reach or be higherthan (½)*Vcc.

In this embodiment, during the normal state, the auxiliary power module1160 supplies power normally when the discharge pin DIS of thecontroller 1166 is triggered. The waveforms of the voltages at thedischarge pin DIS and the output pin OUT are shown in FIG. 12P. FIG. 12Pshows charge-discharge waveform at the discharge pin DIS and the voltagewaveform at the output terminal OUT along the time axis when auxiliarypower module 1160 is in the normal state. As shown in FIG. 12P, when thedischarge pin DIS is triggered, meaning the controller 1166 is in adischarge stage (to discharge the capacitor C5), a low voltage is outputat the output pin OUT. When the discharge pin DIS is not triggered,meaning the controller 1166 is in a charge stage (to charge thecapacitor C5), a high voltage is output at the output pin OUT.Accordingly, the high and low voltage levels output at the output pinOUT are respectively used to control current conduction and cutoff ofthe switch M1.

On the other hand, when the auxiliary power module 1160 is in theabnormal state, charge-discharge waveform at the discharge pin DIS andvoltage waveform at the output pin OUT along the time axis are shown inFIG. 12Q. It is clear from FIGS. 12P and 12Q that no matter whether theauxiliary power module 1160 is in the normal state or the abnormalstate, the period for which the discharge pin DIS is not triggered,which amounts to the period for which the capacitor C5 is charged, isthe same for the two cases. And when auxiliary power module 1160 is inthe abnormal state, since there is a current flowing from the node B tothe discharge pin DIS, which results in the discharge time of thecapacitor C5 being extended, a smaller or relatively small output energyresults at the output side of the transformer or the auxiliary powermodule 1160 and thus the output voltage does not keep increasing, so asto achieve the purpose of open-circuit protection.

In the present embodiment, an example that can be chosen as or toconstitute the control module 1166 is a chip with regulation function bytime, such as a 555 timer IC, for example to control the cutoff periodof the switch M1. And the present embodiment can be implemented by usingresistors and capacitors to achieve the prolonging of discharge time,without using a complicated control scheme. And the voltage range forthe supply voltage Vcc in this embodiment is 4.5V to 16V.

By using circuit in the embodiment discussed above, open-circuit outputvoltage of the auxiliary power module 1160 can be limited to be below aspecific value, such as 300V, which can be determined by choosingappropriate values for parameters in the circuit.

It should be noted that in the circuit of the above embodiment, eachelectrical element or component depicted in the relevant figures, suchas a resistor, capacitor, diode, or MOSFET (as switch M1), is intendedto be a representative or equivalent of any plurality of such an elementthat may be actually used and connected according to relevant rules toimplement this embodiment.

FIG. 12O is a circuit diagram of the auxiliary power module according toan embodiment. Referring to FIG. 12O, the auxiliary power module 1260includes a charging unit 1261 and an auxiliary power unit 1262. Theauxiliary power unit 1262 includes a transformer, a sampling module1264, a control module 1265, and an energy storage unit 1263 forproviding a supply voltage Vcc. The difference between embodiments ofFIG. 12O and FIG. 12N is that the sampling module 1264 in the embodimentof FIG. 12O is implemented by an optical coupler.

The transformer includes a primary winding L1 and a secondary windingL2. Configuration of the primary winding L1 with a switch M1 is the sameas that in the above described embodiment. A dotted terminal of thesecondary winding L2 is electrically connected to the anode of a diodeD1, and a non-dotted terminal of the secondary winding L2 iselectrically connected to an end of a capacitor C1. The cathode of thediode D1 is electrically connected to the other end of the capacitor C1.And the two ends of the capacitor C1 can be regarded as auxiliary powersupply output terminals V1 and V2.

The sampling module 1264 includes an optical coupler PD having at leastone photodiode, whose anode is electrically connected to the cathode ofthe diode D1 and an end of the capacitor C1 and whose cathode iselectrically connected to an end of a resistor R4. The other end of theresistor R4 is electrically connected to an end of a clamping componentRcv, which has the other end electrically connected to the other end ofthe capacitor C1. A bipolar junction transistor in the optical couplerPD has a collector and an emitter electrically connected to two ends ofa resistor R3 respectively.

The control module 1265 includes a controller 1266, capacitors C3, C4and C5, and resistors R2 and R3. The power supply pin VC of thecontroller 1266 is electrically connected to the collector of thebipolar junction transistor in the optical coupler PD. The discharge pinDIS of the controller 1166 is electrically connected to an end of theresistor R2, which has the other end electrically connected to thecollector of the bipolar junction transistor in the optical coupler PD.The sample pin THRS of the controller 1166 is electrically connected tothe emitter of the bipolar junction transistor in the optical coupler PDand is connected to an end of the capacitor C5, which capacitor C5 hasthe other end electrically connected to the ground terminal GND. Theground pin GT of the controller 1166 is grounded to the ground terminalGND. The reset pin RST of the controller 1166 is electrically connectedto an end of the capacitor C3, which has the other end connected to theground terminal GND. The constant voltage pin CV of the controller 1166is electrically connected to an end of the capacitor C4, which has theother end connected to the ground terminal GND. The trigger pin TRIG ofthe controller 1166 is electrically connected to the sample pin THRS.And the output pin OUT of the controller 1166 is electrically connectedto the gate terminal of the switch M1.

What follows here is a description of operations of the circuitembodiment in FIG. 12O. When the auxiliary power module 1260 is in anormal state, the output voltage between the output terminals V1 and V2of the auxiliary power module 1260 is lower than a clamping voltage ofthe clamping component Rcv, so a current I1 flowing through the resistorR4 is small and can be ignored. And a current I2 flowing through thecollector and emitter of the bipolar junction transistor in the opticalcoupler PD is also small.

When the load is in an open-circuit condition, the output voltagebetween the output terminals V1 and V2 of the auxiliary power module1260 increases and, when the output voltage exceeding a thresholdvoltage value of the clamping component Rcv, then conducts the clampingcomponent Rcv, causing the current I1 flowing through the resistor R4 toincrease. The increase of the current I1 then lights up the photodiodeof the optical coupler PD, which causes the current I2 flowing throughthe collector and emitter of the bipolar junction transistor in theoptical coupler PD to proportionally increase. The increase of thecurrent I2 then compensates for discharging of the capacitor C5 throughthe resistor R2, prolonging the discharging time of the capacitor C5 andthereby prolonging the cutoff time of the switch M1 (i.e., reducing theduty cycle of the switch M1). With respect to the output side of thetransformer, this reducing or adjusting of the duty cycle causes asmaller output energy, and thus the output voltage will not keepincreasing, so as to achieve the purpose of open-circuit protection.

In this embodiment of the auxiliary power module 1260, the clampingcomponent Rcv may be or comprise for example a varistor, a transientvoltage suppressor diode (TVS diode), or a voltage regulation diode suchas a Zener diode. The trigger threshold value of the clamping componentRcv may be in the range 100 to 400 V, and is preferably in the range 150to 350 V. In some example embodiments herein, 300 V is chosen as thetrigger threshold value.

In one embodiment of the auxiliary power module 1260, the resistor R4operates mainly to limit current, and its resistance may be in the range20 k to 1 M ohm (the “M” denoting a million) and is preferably in therange 20 k to 500 k ohm. In some disclosed embodiments herein, 50 k ohmis chosen as the resistance of the resistor 6511. And the resistor R3operates mainly to limit current, and its resistance may be in the range1 k to 100 k ohm and is preferably in the range 5 k to 50 k ohm. In thedisclosed embodiments herein, 6 k ohm is chosen as the resistance of theresistor R3. In this embodiment of the auxiliary power module 1260,capacitance of the capacitor C5 may be in the range 1 nF to 1000 nF andis preferably in the range 1 nF to 100 nF. In some disclosed embodimentsherein, 2.2 nF is chosen as the capacitance of the capacitor C5.Capacitance of the capacitor C4 may be in the range 1 nF to 1 pF and ispreferably in the range 5 nF to 50 nF. In some disclosed embodimentsherein, 10 nF is chosen as the capacitance of the capacitor C4. Andcapacitance of the capacitor C1 may be in the range 1 uF to 100 uF andis preferably in the range 1 uF to 10 uF. In some disclosed embodimentsherein, 4.7 uF is chosen as the capacitance of the capacitor C1. Thespecific values for components described above in connection with FIG.12O may be combined in one embodiment, or some of them may be used withother components having different values from the specific valuesdescribed above.

In the embodiments of FIG. 12N and FIG. 12O, the energy storage unit1163 of the auxiliary power module 1160/1260 may comprise for example abattery or a supercapacitor. In the above embodiments, DC power supplyby the auxiliary power module 1160/1260 may be managed by a BMS so as tocharge the capacitor C5 when the LED tube lamp operates in a normallighting mode. Or the capacitor C5 may be charged when the LED tube lampoperates in a normal lighting mode, without the BMS. Through choosingappropriate values of parameters of components of the auxiliary powermodule 1160/1260, a small current, for example not exceed 300 mA, can beused to charge the auxiliary power module 1160/1260.

Advantages of using the auxiliary power module 1160/1260 embodiments ofFIGS. 12N and 12O include that it has relatively simple circuittopology; a specialized integrated circuit chip is not needed toimplement it; relatively few components are used to implement theopen-circuit protection and thus the reliability of the auxiliary powermodule can be improved. The topology of the auxiliary power module1160/1260 can be implemented by an isolation circuit structure so as toreduce the risks of current leakage.

In summary, the principle of using the auxiliary power module 1160/1260embodiments of FIGS. 12N and 12O is to sample an output voltage (orcurrent) as by using the sampling module 1164; and if thevoltage/current sample exceeds a predefined threshold value, to prolongthe cutoff period of the switch M1 by prolonging time of dischargethrough the discharge terminal DIS/THRS of the controller 1166, therebymodulating the duty cycle of the switch M1. The operating voltage at thedischarge terminal DIS/THRS of the controller 1166 is in the rangebetween (⅓)*Vcc and (⅔)*Vcc, each charge time of the capacitor C5 isabout the same, but its discharge time is prolonged. Therefore thisadjusting of the duty cycle causes a smaller output energy, and thus theoutput voltage will not keep increasing, so as to achieve the purpose ofopen-circuit protection.

FIG. 12P shows a time diagram including corresponding waveforms of thevoltage at the OUT terminal and the voltage at the DIS/THRS terminal ofthe control module 1165, when the auxiliary power module is working inthe normal state. FIG. 12Q shows a time diagram including correspondingwaveforms of the voltage at the OUT terminal and the voltage at theDIS/THRS terminal of the control module 1165, when the auxiliary powermodule is in an abnormal state (as when the load is open-circuited). Thevoltage at the OUT terminal is initially at a high level while theDIS/THRS terminal is not triggered (so the capacitor C5 is beingcharged). When the DIS/THRS terminal is triggered (so the capacitor C5is discharging), the voltage at the OUT terminal falls to be at a lowlevel. The waveform or signal of the voltage at the OUT terminal is thusused to control current conduction and cutoff of the switch M1.

FIG. 13A is a block diagram of exemplary LED lighting systems accordingto an exemplary embodiment. Referring to FIG. 13A, compared to the LEDtube lamps 500, 600, 700 and 800 described above in differentembodiments, a power supply module 5 of the LED tube lamp 900 includes arectifying circuit 510, a filtering circuit 520, a driving circuit 530,and further includes an electric-shock detection module 2000 whichincludes a detection control circuit 2100 (which can be referred to adetection controller) and a current-limiting circuit 2200.

In the present embodiment, the detection control circuit 2100 isconfigured to perform an installation state detection/impedancedetection in the LED tube lamp 900, thereby to generate a correspondingcontrol signal according to a detection result, in which the detectionresult indicates whether the LED tube lamp 900 is correctly/properlyinstalled in a lamp socket or whether a foreign external impedance(e.g., human body resistor) contacts the LED tube lamp 900. Thecurrent-limiting circuit 2200 is configured to limit or determinewhether to limit current flowing or to flow through the LED tube lamp900 according to the control signal corresponding to the detectionresult. When the current-limiting circuit 2200 receives the controlsignal indicating that the LED tube lamp 900 is correctly/properlyinstalled in a lamp socket or a foreign external impedance contacts orconnects to the LED tube lamp, the current-limiting circuit 2200 allowsthe power supply module 5 providing electricity to the LED module 50normally (i.e., the current-limiting circuit 2200 allows the current tonormally flow through the power loop of the LED tube lamp 900). When thecurrent-limiting circuit 2200 receives the control signal indicatingthat the LED tube lamp 900 is incorrectly/improperly installed in a lampsocket or a foreign external impedance contacts or connects to the LEDtube lamp 900, the current-limiting circuit 2200 limits a current toflow through the LED tube lamp 900 to being under a safety threshold toavoid electric shock hazards. The safety threshold is for example 5 MIUas a root-mean-square (rms) value or 7.07 MIU as a peak value.

The power loop in the LED tube lamp 900 may refer to a path or a routefor transmitting current from the power supply module 5 to the LEDmodule 50. The installation state detection or the impedance detectionmay refer to a circuit operation for obtaining information on aninstallation state of or equivalent impedance in the LED tube lamp 900by detecting electrical characteristics (such as voltage or current).Further, in some embodiments, the detection control circuit 2100performs detection of electrical characteristics by controlling currentcontinuity on the power loop or forming an additional detection path,which may reduce the risk of electric shock during performing detection.Detailed descriptions of specific circuit embodiments explaining how adetection control circuit performs detection of electricalcharacteristics are presented below with reference to FIGS. 14-41G.

FIG. 13B is a block diagram of exemplary LED lighting systems accordingto another exemplary embodiment. Referring to FIG. 13B, compared to theembodiment of FIG. 13A, an electric-shock detection module 2000 of FIG.13B is disposed external to the LED tube lamp 1000 and on a power supplypath from an external AC power supply (e.g., AC grid) 508, and is forexample disposed in a lamp socket or fixture. When external connectionpins of the LED tube lamp 1000 are electrically connected to theexternal AC power supply 508, the electric-shock detection module 2000is serially connected to a power loop in the LED tubal lamp 1000 throughthe corresponding pin(s), thereby the shock detection module 2000 canperform installation state detection/impedance detection in such ways asdescribed above in FIG. 13A to determine whether the LED tube lamp 1000is correctly/properly installed in a lamp socket or whether a user isexposed to risk of electric shock on the LED tube lamp 1000. In thisembodiment of FIG. 13B, the configuration of the electric-shockdetection module 2000 is similar to that in the embodiment of FIG. 13A,so it is not repeated herein.

In another embodiment, the structures of the power supply module inembodiments of FIG. 13A and FIG. 13B can be integrated. For example, aplurality of the electric-shock detection modules 2000 may be disposedin a lighting system of an LED tube lamp, wherein at least one of theelectric-shock detection modules 2000 may be disposed on an internalpower loop of the LED tube lamp, and at least another one of theelectric-shock detection modules 2000 may be disposed to be external tothe LED tube lamp, and for example disposed in the lamp socket. Thisexternal electric-shock detection module 2000 can be electricallyconnected to an internal power loop of the LED tube lamp through pins onan end cap of the LED tube lamp, to improve effects of protection fromaccidental electric shock.

FIG. 13C is a block diagram of an LED tube lamp lighting systemaccording to another embodiment. Referring to FIG. 13C, compared to theembodiments of FIGS. 13A and 13B, an LED tube lamp 1600 in thisembodiment of FIG. 13C is for example a Type-C LED tube lamp as having apower module 5 disposed external to the LED tube lamp 1600. Anelectric-shock detection module 2000 is disposed within the LED tubelamp 1600 and includes a detection control circuit 2100 and acurrent-limiting circuit 2200. In this embodiment of FIG. 13C, thecurrent-limiting circuit 2200 may be disposed on a power supply path andis controlled by the detection control circuit 2100. Specific operationsand details of the electric-shock detection module 2000 are similar tothose in other analogous embodiments described herein, and thus are notdescribed in detail again. It's worth noting that in applications ofthis embodiment, due to the functions of the electric-shock detectionmodule 2000, there is substantially no risk of occurrence ofelectric-shock hazards even if a non-isolation type of power conversioncircuit is chosen as the external power module 5. In contrast to anexternal power module designed for supplying a traditional LED tube lamptypically requiring an isolation type of power conversion circuit, thedesign of an external power module in embodiments of the presentinvention is not limited to using an isolation type of power conversioncircuit, and so the design choice thereof is more diversified.

It should be noted that the described shock detection module 2000 ineither FIG. 13A or FIG. 13B is configured to be used in or with a powersupply module of an LED tube lamp, which can be implemented, partiallyor entirely, by a discrete circuit or an integrated circuit, to whichthe present invention is not limited. In addition, the designation“shock detection module” herein for the module 2000 in FIGS. 13A and 13Bserves to be representative but not to limit the scope of the module2000 or the claimed invention. The scope of the “shock detection module”2000 as described herein and as may be reflected in the claimsencompasses any arrangement of a circuit or module comprising electricalcomponents with their operations, functional/structural configurations,and connections consistent with or according to the relevantdescriptions herein thereof. In practice and this disclosure, accordingto different ways of description, the shock detection module 2000 may bealternatively referred to as, but its different formulations are notlimited to, a detection circuit, an installation detectionmodule/circuit, a shock protection module/circuit, a shock protectiondetection module/circuit, an impedance detection module/circuit, ordirectly expressed as a circuitry for such a purpose. In addition, FIGS.13A and 13B are diagrams merely to illustrate exemplary connectionrelationships between an LED tube lamp 900/1000 and an external powersupply 508, but they are not to limit an external driving signal fromthe external power supply 508 to only being applied in a single-endedpower-supply configuration at one end of the LED tube lamp 900/1000.

Explanatory descriptions of different schematic circuit and functionalblock embodiments under the embodiment configuration of FIG. 13A where ashock detection module 2000 is disposed inside the LED tube lamp 900 arepresented below.

Referring to FIG. 14, a block diagram of an LED tube lamp including apower supply module according to some exemplary embodiments isillustrated. Compared to the LED lamp shown in FIG. 5A, the LED tubelamp 1100 of FIG. 14 includes a rectifying circuit 510, a filteringcircuit 520, and a driving circuit 530, and further includes anelectric-shock detection module 3000 (also known as an electric shockprotection module). In these embodiments, the LED tube lamp 1100 isconfigured to, for example, directly receive the external driving signalprovided by the external AC power supply 508, wherein the externaldriving signal is input through the signal line (marked as “L”) and theneutral line (marked as “N”) to the two pins 501 and 502 on the two endsof the LED tube lamp 1100. In practical applications, the LED tube lamp500 may further comprise two additional pins 503 and 504, also on itstwo ends as shown in FIG. 14. Under the structure of the LED tube lamp1100 having the four pins 501-504, depending on design needs the twopins (such as the pins 501 and 503, or the pins 502 and 504) on an endcap disposed on one end of the LED tube lamp 1100 may be electricallyconnected or mutually electrically independent, but this invention isnot limited to any of the two different cases.

The electric-shock detection module 3000 is disposed inside the LED tubelamp 1100 and includes a detection control circuit 3100 and acurrent-limiting circuit 3200. The electric-shock detection module 3000may be and is hereinafter referred to as an installation detectionmodule 3000. The current-limiting circuit 3200 is coupled to therectifying circuit 510 via an installation detection terminal TE1 and iscoupled to the filtering circuit 520 via an installation detectionterminal TE2. So the current-limiting circuit 3200 is serially coupledto a power loop of the LED tube lamp 1100. Under a detection mode, thedetection control circuit 3100 detects the signal passing through theinstallation detection terminals TE1 and TE2 (i.e., the signal passingthrough the power loop) and determines whether to cut off an LED drivingsignal (e.g., an external driving signal) passing through the LED tubelamp based on the detected result. The installation detection module3000 includes circuitry configured to perform the steps of detecting thesignal passing through the installation detection terminals TE1 and TE2and determining whether to cut off an LED driving signal, and thus maybe referred to as an installation detection circuit, or more generallyas a detection circuit or cut-off circuit. When the LED tube lamp 1100is not yet installed in a lamp socket or holder, or in some cases if itis not installed properly or is only partly installed (e.g., one side isconnected to a lamp socket, but not the other side yet), the detectioncontrol circuit 3100 detects a smaller current compared to apredetermined current (or current value) and determines the signal ispassing through a high impedance through the installation detectionterminals TE1 and TE2. In this case, in certain embodiments, thecurrent-limiting circuit 3200 is in a cut-off state to make the LED tubelamp 1100 stop working or limit the current flowing through the powerloop to less than 5 MIU, which can be referred to 5 mA at a certainfrequency and is the requirement, defined in the safety certificationstandard such as UL, of the LED tube lamp. In this manner, when theinstallation detection circuit 2520 is in the cut-off state, the LEDmodule is not capable of emitting light because the current flowingthrough the power loop is limited. The unit of “MIU” is defined byAmerican National Standards Institute (ANSI) C101-1992.

Otherwise, the installation detection module 2520 determines that theLED tube lamp has already been installed in the lamp socket or holder(e.g., when the detection control circuit 3100 detects a current equalto or greater than a predetermined current, and the current-limitingcircuit 3200 determines the signal is passing through a low impedancethrough the installation detection terminals TE1 and TE2) and maintainsconducting state/current limiting state to make the LED tube lamp 1100working normally. In this manner, when the current-limiting circuit 3200is in the conducting state, the LED module is capable of emitting lightbecause the current flowing through the power loop is not limited.

For example, in some embodiments, when a current passing through theinstallation detection terminals TE1 and TE2 is greater than or equal toa specific, defined installation current (or a current value), which mayindicate that the current supplied to the driving circuit 530 is greaterthan or equal to a specific, defined operating current, thecurrent-limiting circuit 3200 is conducting to make the LED tube lamp1100 operate in a conducting state. For example, a current greater thanor equal to the specific current value may indicate that the LED tubelamp 1100 has correctly been installed in the lamp socket or holder.When the current passing through the installation detection terminalsTE1 and TE2 is smaller than the specific, defined installation current(or the current value), which may indicate that the current supplied tothe driving circuit 530 is less than a specific, defined operatingcurrent, the current-limiting circuit 3200 cuts off current to make theLED tube lamp 1100 enter in a non-conducting state based on determiningthat the LED tube lamp 1100 has been not installed in, or does notproperly connect to, the lamp socket or holder. In other words, theinstallation detection module 3000 determines conducting or cutting offbased on the impedance detection to make the LED tube lamp operate in aconducting state or enter non-conducting state. The LED tube lampoperating in a conducting state may refer to the LED tube lamp includinga sufficient current passing through the LED module to cause the LEDlight sources to emit light. The LED tube lamp operating in a cut-offstate may refer to the LED tube lamp including an insufficient currentor no current passing through the LED module so that the LED lightsources do not emit light. Accordingly, the occurrence of electric shockcaused by touching the conductive part of the LED tube lamp which isincorrectly installed in the lamp socket or holder can be efficientlyavoided.

When (part of) a human body touches or contacts the LED tube lamp, someimpedance of the human body may cause a change in equivalent impedanceon a power loop in the LED tube lamp, so the installation detectionmodule 3000 can determine whether a human body has touched or contactedthe LED tube lamp by e.g. detecting a change in current/voltage on thepower loop, in order to implement the function of electric-shockprevention. The installation detection module 3000 can determine whetherthe LED tube lamp is correctly/properly installed into a lamp socket orwhether the body of a user has accidentally touched a conducting part ofthe LED tube lamp which is not yet correctly/properly installed into alamp socket, by detecting an electrical signal such as a voltage orcurrent. In addition, compared with a general LED power supply module,since the power supply module provided with the installation detectionmodule 3000 has the effect of preventing electric shock, there is noneed to dispose a safety capacitor (i.e., X capacitor) between the inputterminals of the rectifying circuit 510 (i.e., between the live wire (L)and the neutral wire (N)). From the perspective of the equivalentcircuit of the power supply module, having no X capacitor disposedbetween the input terminals of the rectifying circuit 510 means theeffective capacitance between the input terminals of the rectifyingcircuit 510 is, for example, smaller than 47 nF. In the presentembodiment, the power loop refers to the current path in the LED tubelamp, for example, the path formed between the pins on the respectiveend caps.

More precisely, when an external AC power supply is applied to the LEDtube lamp 500, the current flows from the pin on one end cap (e.g., leftend cap) to the pin on the other end cap (e.g., right end cap) andpasses through the leads and the components serially connected to thefirst terminal of the LED module (e.g., the positive terminal), the LEDmodule, the leads and the components serially connected to the secondterminal of the LED module (e.g., the negative terminal) in sequence.The pins, the leads, the components, and the LED module that the currentpasses through form the power loop.

It should be noted that, the issue of electric shock is raised since thepower loop is formed between the respective ends of the LED tube lampunder the dual-end power supply structure.

It is noted that the illustrated position of the installation detectionmodule 2520 in FIG. 14 is merely an exemplary position determinedaccording to a possible or illustrated position of the current-limitingcircuit 3200 in the installation detection module 3000, so figuresillustrating the current-limiting circuit 3200 do not mean that thecurrent-limiting circuit 3200 must be disposed in the same position asin FIG. 14 for connecting to other circuit(s) (such as the rectifyingcircuit 510, the filtering circuit 520, or the driving circuit 530).Further, it is merely an example embodiment to dispose thecurrent-limiting circuit 3200 between the rectifying circuit 510 and thefiltering circuit 520. In some embodiments, the function of preventingelectric shock can be implemented by disposing the current-limitingcircuit 3200 at the position that is capable of controlling turn-on andcut-off state of the power loop. For example, the switch circuit may bedisposed between the driving circuit (530) and the LED module (50), butthe present invention is not limited thereto.

From circuit operation perspectives, a method performed by the detectioncontrol circuit 3100 and configured to determine, under a detectionmode, whether the LED tube lamp 1100 is correctly/properlyconnected/installed to a lamp socket or whether there is any unintendedexternal impedance being connected to the LED tube lamp is shown in FIG.44A. The method includes the following steps: temporarily conducting adetection path for a period and then cutting it off (step S101);sampling an electrical signal on the detection path during theconduction period (step S102); determining whether the sample ofelectrical signal conforms with predefined signal characteristics (stepS103); if the determination result in step S103 is positive, controllingthe current-limiting circuit 3200 to operate in a first state (stepS104); and if the determination result in step S103 is negative,controlling the current-limiting circuit 3200 to operate in a secondstate (step S105) and then returning to the step S101.

In the method of FIG. 44A, the detection path may refer to the powerloop in the LED tube lamp described above or an independent current pathcoupled to an output terminal of the rectifying circuit 510 of FIG. 18.And detailed description of some embodiments of the method is presentedbelow with reference to FIGS. 15A to 22B. And detailed description ofhow the described detection control circuit 3100 sets parameters such asthe conduction period, intervals between multiple conduction periods,and the time point to trigger conduction, of the detection path is alsopresented below of different embodiments.

In the step S101, conducting the detection path for a period may beimplemented by means using pulse signal to control switching of aswitch.

In the step S102, the sample of electrical signal is a signal that canrepresent or express impedance variation on the detection path, whichsignal may comprise a voltage signal, a current signal, a frequencysignal, a phase signal, etc.

In the step S103, the operation of determining whether the sampledelectrical signal conforms with predefined signal characteristics maycomprise, for example, a relative relation of the sampled electricalsignal to a predefined signal. In some embodiments, the sampledelectrical signal that is determined to conform with the predefinedsignal characteristics may correspond to a determination or state thatthe LED tube lamp is correctly/properly connected to the lamp socket orthere is no unintended external impedance being coupled to the LED tubelamp, and the sampled electrical signal that is determined to notconform with the predefined signal characteristics may correspond to adetermination or state where the LED tube lamp is not correctly/properlyconnected to the lamp socket or there is a foreign external impedance(e.g., a human body impedance, simulated/test human body impedance, orother impedance connected to the lamp and which the lamp is not designedto connect to for proper lighting operations) being coupled to the LEDtube lamp.

In the steps S104 and S105, the first state and the second state are twodistinct circuit-configuration states, and may be set according to theconfigured position and type of the current-limiting circuit 3200. Forexample, in the case or embodiment where the current-limiting circuit3200 is independent of the driving circuit and refers to a switchingcircuit or a current-limiting circuit that is connected on the powerloop in series, the first state refers to a conducting state (ornon-current-limiting state) while the second state refers to a cutoffstate (or current-limiting state).

Detailed operations and example circuit structures for performing theabove method in FIG. 44A are illustrated by descriptions below ofdifferent embodiments of installation detection modules.

Referring to FIG. 15A, a block diagram of an installation detectionmodule according to some certain embodiments is illustrated. Theinstallation detection module 3000 a includes a detection pulsegenerating module 3110, a detection result latching circuit 3120, adetection determining circuit 3130 and a current-limiting circuit 3200a. The detection pulse generating module 3110, detection result latchingcircuit 3120, and detection determining circuit 3130 constitute adetection control circuit 3100. Certain of these circuits or modules maybe referred to as first, second, third, etc., circuits as a namingconvention to differentiate them from each other. The detectiondetermining circuit 3130 is coupled to and detects the signal betweenthe installation detection terminals TE1 (through a switch circuitcoupling terminal 3201 and the current-limiting circuit 3200 a) and TE2.The detection determining circuit 3130 is also coupled to the detectionresult latching circuit 3120 via a detection result terminal 3131 totransmit the detection result signal to the detection result latchingcircuit 3120. The detection determining circuit 3130 may be configuredto detect a current passing through terminals TE1 and TE2 (e.g., todetect whether the current is above or below a specific current value).The detection pulse generating module 3110 is coupled to the detectionresult latching circuit 3120 via a pulse signal output terminal 3111,and generates a pulse signal to inform the detection result latchingcircuit 3120 of a time point for latching (storing) the detectionresult. For example, the detection pulse generating module 3110 may be acircuit configured to generate a signal that causes a latching circuit,such as the detection result latching circuit 3120 to enter and remainin a state that corresponds to one of a conducting state or a cut-offstate for the LED tube lamp. The detection result latching circuit 3120stores the detection result according to the detection result signal (ordetection result signal and pulse signal), and transmits or provides thedetection result to the current-limiting circuit 3200 a coupled to thedetection result latching circuit 3120 via a detection result latchingterminal 3121. The current-limiting circuit 3200 a controls the statebetween conducting or cut off between the installation detectionterminals TE1 and TE2 according to the detection result. In someembodiments, the current-limiting circuit 3200 a comprises a switchingcircuit, and in the following description is referred to as theswitching circuit 3200 a.

In some embodiments, the installation detection module 3000 a furtherincludes an emergency control module 3140 configured for determiningwhether an external driving signal is a DC signal provided by anauxiliary power supply module, in order for the detection resultlatching circuit 3120 to adjust its way of controlling the switchingcircuit 3200 according to the determination result, so as to avoidmisoperation by the installation detection module 3000 a when the LEDtube lamp is used in an environment/application to be receivingauxiliary power input by an auxiliary power supply module. Thestructures and operations of other circuit(s)/module(s) in theseembodiments with the emergency control module 3140 are similar to orcorrespond to those of the detection pulse generating module 3110,detection result latching circuit 3120, detection determining circuit3130, and the switching circuit 3200 described above, and thus are notrepeated herein.

Specifically, the emergency control module 3140 is connected to adetection result latching circuit 3120 through a path 3141, and isconfigured to detect a bus voltage of the power supply module anddetermine whether the external driving signal being received by the LEDtube lamp is a DC signal. If the emergency control module 3140determines that the external driving signal is a DC signal, theemergency control module 3140 outputs a first state signal indicative ofan emergency state to the detection result latching circuit 3120; or ifthe emergency control module 3140 determines that the external drivingsignal is not a DC signal, the emergency control module 3140 outputs asecond state signal indicative of a non-emergency state to the detectionresult latching circuit 3120. When the detection result latching circuit3120 receives the first state signal, regardless of the output of thedetection pulse generating module 3110 and the output of the detectiondetermining circuit 3130, the detection result latching circuit 3120then maintains the switch circuit 3200 in a conduction or on state,which can be referred to as in an emergency lighting mode. On the otherhand, when the detection result latching circuit 3120 receives thesecond state signal, the detection result latching circuit 3120 thenoperates according to its ordinary mechanism to control the conductionand cutoff of the switch circuit 3200 a based on the pulse signal andthe detection result signal. Such a term “bus voltage” mentioned hereinmay refer to an alternating voltage/signal provided to an LED tube lampwhich has not been processed by a rectifying circuit (i.e., not yetrectified, such as the external driving signal) in the LED tube lamp, ormay refer to a rectified voltage/signal after rectification in the LEDtube lamp and based on such an external driving signal, but the presentinvention is not limited to any of these two cases.

Next, detailed operation mechanisms of an installation detection moduleincluding the emergency control module 3140 are further described withreference to FIG. 44B. FIG. 44B is a flow chart of steps of a controlmethod of the installation detection module with the emergency controlmodule 3140 according to an exemplary embodiment. Referring to both FIG.15A and FIG. 44B, when a power supply module of the LED tube lampreceives an external driving signal, the emergency control module 3140operates to detect voltage on the power line (step S201) and then todetermine whether the detected voltage on the power line is maintainedabove a first voltage level for a first period (step S202), wherein thefirst period may be for example 75 ms, and the first voltage level maybe any level in the range of between 100V and 140V, such as 110V or120V. For example, in an embodiment of the step S202, the emergencycontrol module 3140 judges whether the detected voltage on the powerline is maintained above 110V or 120V for over 75 ms.

If the determination result by the emergency control module 3140 in stepS202 is positive, this means the received external driving signal is aDC signal, then the installation detection module 2520 enters into anemergency mode and causes the detection result latching circuit 3120 todirect the switch circuit 3200 to operate in a first configuration state(step S203), which is for example a conduction state. On the other hand,if the judgment by the emergency control module 3140 in step S202 isnegative, this means the received external driving signal is not a DCsignal but is an AC signal, then the installation detection module 2520enters into a detection mode, causing the detection result latchingcircuit 3120 to judge the installation state of the LED tube lamp byoutputting pulse(s) or pulse signal(s) to the switch circuit 3200. Fordetailed descriptions of operations of the installation detection module2520 that includes the emergency control module 3140 under theinstallation detection mode according to certain embodiments, refer tothose of embodiments of FIG. 44A presented above.

On the other hand, under the emergency mode, in addition to maintainingthe switch circuit 3200 a to operate in the first configuration, theemergency control module 3140 further determines whether a bus voltage(i.e., the voltage on the power line of the power supply module) risesto exceed a second voltage level (step S204). When the emergency controlmodule 3140 determines the bus voltage does not rise to exceed thesecond voltage level, which refers to the LED tube lamp remaining underthe emergency mode, the switch circuit 3200 continues to operate in thefirst configuration. When the emergency control module 3140 determinesthe bus voltage rises to exceed the second voltage level from the firstvoltage level, which refers to the external driving signal received bythe power supply module changing into the AC signal from the DC signal(e.g., AC power line has been recovered), the emergency control module3140 controls the installation detection module 3000 a to enter into thedetection mode. In some embodiments, the second voltage level can be anyvoltage level higher than the first voltage level but less than 277V.For example, when the first voltage level is 110V, the second voltagelevel can be 120V. According to some embodiments of the step S204, theemergency control module 3140 determines whether the bus voltage has arising edge exceeding 120V, and enters into the detection mode when thedetermination result is positive.

In some embodiments, the installation detection module 3000 a furtherincludes a ballast detection module 3400 (illustrated in FIG. 15A),which is configured for determining whether the external driving signalinput to the LED tube lamp is an AC signal provided by an electronicballast, so that the detection result latching circuit 3120 can adjustthe way of controlling the switching circuit 3200 a according to thedetermination result. For example, in case a ballast-bypass type LEDtube lamp is installed, by mistake, onto a lamp socket with a ballast,the LED tube lamp having the ballast detection module 3400 is capable ofissuing a warning (such as a flashing) to the user of such a misuseoccurrence. Therefore, the damage caused by an AC signal provided from aballast, which is not designed to drive the ballast-bypass type LED tubelamp, can be prevented.

Specifically, the ballast detection module 3400 of FIG. 19A is coupledto the detection result latching circuit 3120 through a path 3151, andis configured to detect the bus voltage in the power supply module ofthe LED tube lamp. In addition, the ballast detection module 3400 isconfigured to determine whether the external driving signal being inputto the LED tube lamp is an AC signal provided by an electronic ballastor directly by a power grid (i.e., AC main), according to a detectedsignal feature of the power line voltage signal. Since an AC signaloutput by a ballast (especially an electronic ballast) hascharacteristics of having relatively high frequency and/or high voltage,but an AC signal output by the power grid typically has characteristicsof having relatively low frequency (such as in the range of 50 Hz to 60Hz) and/or low voltage (generally lower than 305V), the source of anexternal driving signal input to the LED tube lamp can be identified bydetecting a signal feature, such as the frequency, amplitude, or phase,of the power line voltage signal input in a power supply module of theLED tube lamp.

For example, in some embodiments, the ballast detection module 3400 isconfigured to sample a signal at rectifying output terminal 511/512 anddetermine or detect the frequency of the sampled signal, which can bereferred to as the frequency of the bus voltage. When the signalfrequency detected by the ballast detection module 3400 is greater thana set value, this indicates that the currently input external drivingsignal is a relatively high frequency signal and is thus likely providedby a ballast, so the ballast detection module 3400 then issues a firstindicating signal (indicative of the external driving signal beingprovided by a ballast) to the detection result latching circuit 3120,which then controls the switching state of the switching circuit 3200 aaccording to the first indicating signal, so as to affect the continuityof current in the power loop of the LED tube lamp. On the other hand,when the signal frequency detected by the ballast detection module 3400is smaller than or equal to the set value, this indicates that thecurrently input external driving signal is a relatively low frequencysignal and is thus likely provided by an AC power grid, so the ballastdetection module 3400 then issues a second indicating signal (indicativeof the external driving signal being provided by an AC power grid) tothe detection result latching circuit 3120, which then controls tomaintain the switching circuit 3200 a in a conducting state according tothe second indicating signal, so as to cause the input driving signal tobe stably provided to a later-stage LED module, thereby causing the LEDmodule to have consistent, smooth, and/or even luminance.

When the input external driving signal detected by the ballast detectionmodule 3400 is provided by a ballast, the LED module is configured togenerate or emit a specific light pattern in response to variation inthe continuity of a current flowing in the power loop, in order tofurther indicate to a user an occurrence of a misuse installation. Insome embodiments, the specific light pattern may be referred to as aflashing of light of a constant frequency or variable frequency. Forexample, when receiving the first indicating signal the detection resultlatching circuit 3120 may be configured to periodically turn on and thenturn off the switching circuit 3200 a, causing the magnitude of adriving current to be affected by the switching of the switching circuit3200 a, in order to change luminance of the LED module accordingly toperform a flashing mode. A user can notice that the ballast-bypass LEDtube lamp has been installed by mistake to a lamp socket of a ballast,when observing that the LED tube lamp is flashing in the flashing mode,and can thus immediately remove the LED tube lamp from the socket of aballast to prevent damage or danger.

In some embodiments, the installation detection module 3000 a furtherincludes a warning circuit 3160 (illustrated in FIG. 19A), which isconfigured to issue a misuse warning in the form of e.g. sound or light,under the control of the detection result latching circuit 3120, whenthere is a misuse condition or risk happening on the LED tube lamp, inorder to remind or alert a user of the occurrence of misuse condition.In the illustrated embodiment of FIG. 19A, the warning circuit 3160electrically connected to the detection result latching circuit 3120through a path 3161, in order to receive a signal issued by thedetection result latching circuit 3120. When receiving the firstindicating signal, the detection result latching circuit 3120 issues asignal to enable the warning circuit 3160 to issue a misuse warning. Insome embodiments, the warning circuit 3160 comprises or is embodied by abuzzer, in order to buzz to alert the user of the misuse situation whenthe ballast-bypass LED tube lamp is installed, by mistake, onto a lampsocket with a ballast.

In some embodiments, the installation detection module 3000 a turns theswitching circuit 3200 a off to maintain the power loop in a cutoffstate after issuing a misuse warning, and thereby avoiding the potentialdanger to a user due to not immediately removing the LED tube lamp fromthe incompatible lamp socket.

In some embodiments, the detection pulse generating module 3110 may bereferred to as a first circuit 3110, the detection result latchingcircuit 3120 may be referred to as a second circuit 3120, the switchcircuit 3200 may be referred to as a third circuit 3200, the detectiondetermining circuit 3130 may be referred to as a fourth circuit 3130,the switch circuit coupling terminal 3201 may be referred to as a firstterminal 3201 and the detection result terminal 3131 may be referred toas a second terminal 3131, the pulse signal output terminal 3111 may bereferred to as a third terminal 3111, the detection result latchingterminal 3121 may be referred to as a fourth terminal 3121, theinstallation detection terminal TE1 may be referred to as a firstinstallation detection terminal TE1, and the installation detectionterminal TE2 may be referred to as a second installation detectionterminal TE2. In this exemplary embodiment, the fourth circuit 3130 iscoupled to the third circuit 3200 and the second circuit 3120 via thefirst terminal 3201 and the second terminal 3131, respectively, thesecond circuit 3120 is also coupled to the first circuit 3110 and thethird circuit 3200 via the third terminal 3111 and the fourth terminal3121, respectively.

In some embodiments, the fourth circuit 3130 is configured for detectinga signal between the first installation detection terminal TE1 and thesecond installation detection terminal TE2 through the first terminal3201 and the third circuit 3200. For example, because of the aboveconfiguration, the fourth circuit 3130 is capable of detecting anddetermining whether a current passing through the first installationdetection terminal TE1 and the second installation detection terminalTE2 is below or above a predetermined current value and transmitting orproviding a detection result signal to the second circuit 3120 via thesecond terminal 3131.

In some embodiments, the first circuit 3110 generates a pulse signalthrough the second circuit 3120 to make the third circuit 3200 workingin a conducting state during the pulse signal. Meanwhile, as a result,the power loop of the LED tube lamp between the installation detectionterminals TE1 and TE2 is thus conducting as well. The fourth circuit3130 detects a sample signal on the power loop and generates a signalbased on a detection result to inform the second circuit 3120 of a timepoint for latching (storing) the detection result received by the secondcircuit 3120 from the fourth circuit 3130. For example, the fourthcircuit 3130 may be a circuit configured to generate a signal thatcauses a latching circuit, such as the second circuit 3120 to enter andremain in a state that corresponds to one of a conducting state or acut-off state for the LED tube lamp. The second circuit 3120 stores thedetection result according to the detection result signal (or detectionresult signal and pulse signal), and transmits or provides the detectionresult to the third circuit 3200 coupled to the second circuit 3120 viathe fourth terminal 3121. The third circuit 3200 receives the detectionresult transmitted from the second circuit 3120 and controls the statebetween conducting or cut off between the installation detectionterminals TE1 and TE2 according to the detection result. It should benoted that the labels “first,” “second,” “third,” etc., described inconnection with these embodiments can be interchangeable and are merelyused here in order to more easily differentiate the different circuits,nodes, and other components from each other.

In some embodiments, the first circuit 3110, the second circuit 3120 andthe fourth circuit 3130 can be referred to a detection circuit or anelectric shock detection/protection circuit, which is configured tocontrol the switching state of the switch circuit/third circuit 3200.

In some embodiments, the detection pulse generating module 3110,detection determining circuit 3130, detection result latching circuit3120, and the switching circuit 3200 of the installation detectionmodule 3000 a comprise or are implemented by, but are not limited to,circuit structures of FIGS. 15B-15F respectively, which FIGS. arecircuit structure diagrams of respective circuits and module of aninstallation detection module 3000 a according to a first embodiment.Descriptions of the circuit embodiments of FIGS. 15B-15F are presentedbelow.

Referring to FIG. 15B, a block diagram of a detection pulse generatingmodule according to some certain embodiments is illustrated. A detectionpulse generating module 3110 may be a circuit that includes multiplecapacitors C11, C12, and C13, multiple resistors R11, R12, and R13, twobuffers BF1 and BF2, an inverter INV, a diode D11, and an OR gate OG1.The capacitor C11 may be referred to as a first capacitor C11, thecapacitor C12 may be referred to as a second capacitor C12, and thecapacitor C13 may be referred to as a third capacitor C13. The resistorR11 may be referred to as a first resistor R11, the resistor R12 may bereferred to as a second resistor R12, and the resistor R13 may bereferred to as a third resistor R13. The buffer BF1 may be referred toas a first buffer BF1 and the buffer BF2 may be referred to as a secondbuffer BF2. The diode D11 may be referred to as a first diode D11 andthe OR gate OG1 may be referred to as a first OR gate OG1. With use oroperation, the capacitor C11 and the resistor R11 connect in seriesbetween a driving voltage (e.g., a driving voltage source, which may bea node of a power supply), such as VCC usually defined as a high logiclevel voltage, and a reference voltage (or potential), such as groundpotential in this embodiment. The connection node between the capacitorC11 and the resistor R11 is coupled to an input terminal of the bufferBF1. In this exemplary embodiment, the buffer BF1 includes two invertersconnected in series between an input terminal and an output terminal ofthe buffer BF1. The resistor R12 is coupled between the driving voltage,e.g., VCC, and an input terminal of the inverter INV. The resistor R13is coupled between an input terminal of the buffer BF2 and the referencevoltage, e.g. ground potential in this embodiment. An anode of the diodeD11 is grounded and a cathode of the diode D11 is coupled to the inputterminal of the buffer BF2. First ends of the capacitors C12 and C13 arejointly coupled to an output terminal of the buffer BF1, and second,opposite ends of the capacitors C12 and C13 are respectively coupled tothe input terminal of the inverter INV and the input terminal of thebuffer BF2. In this exemplary embodiment, the buffer BF2 includes twoinverters connected in series between an input terminal and an outputterminal of the buffer BF2. An output terminal of the inverter INV andan output terminal of the buffer BF2 are coupled to two input terminalsof the OR gate OG1. According to certain embodiments, the voltage (orpotential) for “high logic level” and “low logic level” mentioned inthis specification are all relative to another voltage (or potential) ora certain reference voltage (or potential) in circuits, and further maybe described as “high logic level” and “low logic level.”

FIG. 41A is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. The installation detectionoperation is described further in accordance with FIG. 41A, which showsan example when an end cap of an LED tube lamp is inserted into a lampsocket and the other end cap thereof is electrically coupled to a humanbody, or when both end caps of the LED tube lamp are inserted into thelamp socket (e.g., at the timepoint ts), the LED tube lamp is conductivewith electricity. At this moment, the installation detection module(e.g., the installation detection module 2520 as illustrated in FIG. 14)enters a detection mode DTM. The voltage on the connection node of thecapacitor C11 and the resistor R11 is high initially (equals to thedriving voltage, VCC) and decreases with time to zero finally. The inputterminal of the buffer BF1 is coupled to the connection node of thecapacitor C11 and the resistor R11, so the buffer BF1 outputs a highlogic level signal at the beginning and changes to output a low logiclevel signal when the voltage on the connection node of the capacitorC11 and the resistor R11 decreases to a low logic trigger logic level.As a result, the buffer BF1 is configured to produce an input pulsesignal and then remain in a low logic level thereafter (stops outputtingthe input pulse signal.) The width for the input pulse signal may bedescribed as equal to one (initial setting) time period, which isdetermined by the capacitance value of the capacitor C11 and theresistance value of the resistor R11.

Next, the operations for the buffer BF1 to produce the pulse signal withthe initial setting time period will be described below. Since thevoltage on a first end of the capacitor C12 and on a first end of theresistor R12 is equal to the driving voltage VCC, the voltage on theconnection node of both of them is also a high logic level. The firstend of the resistor R13 is grounded and the first end of the capacitorC13 receives the input pulse signal from the buffer BF1, so theconnection node of the capacitor C13 and the resistor R13 has a highlogic level voltage at the beginning but this voltage decreases withtime to zero (in the meantime, the capacitor stores the voltage beingequal to or approaching the driving voltage VCC.) Accordingly, initiallythe inverter INV outputs a low logic level signal and the buffer BF2outputs a high logic level signal, and hence the OR gate OG1 outputs ahigh logic level signal (a first pulse signal DP1) at the pulse signaloutput terminal 3111. At this moment, the detection result latchingcircuit 3120 (as illustrated in FIG. 15A) stores the detection resultfor the first time according to the detection result signal Sdr receivedfrom the detection determining circuit 3130 (as illustrated in FIG. 15A)and the pulse signal generated at the pulse signal output terminal 3111.During that initial pulse time period, as illustrated in FIG. 15A, thedetection pulse generating module 3110 outputs a high logic levelsignal, which results in the detection result latching circuit 3120outputting the result of that high logic level signal.

When the voltage on the connection node of the capacitor C13 and theresistor R13 decreases to the low logic trigger logic level, the bufferBF2 changes to output a low logic level signal to make the OR gate OG1output a low logic level signal at the pulse signal output terminal 3111(stops outputting the first pulse signal DP1.) The width of the firstpulse signal DP1 output from the OR gate OG1 is determined by thecapacitance value of the capacitor C13 and the resistance value of theresistor R13.

The operation after the buffer BF1 stops outputting the pulse signal isdescribed as below. For example, the operation may be initially in anLED operating mode DRM. Since the capacitor C13 stores the voltage beingalmost equal to the driving voltage VCC, and when the buffer BF1instantaneously changes its output from a high logic level signal to alow logic level signal, the voltage on the connection node of thecapacitor C13 and the resistor R13 is below zero but will be pulled upto zero by the diode D11 rapidly charging the capacitor C13. Therefore,the buffer BF2 still outputs a low logic level signal.

In some embodiments, when the buffer BF1 instantaneously changes itsoutput from a high logic level signal to a low logic level signal, thevoltage on the one end of the capacitor C12 also changes from thedriving voltage VCC to zero instantly. This makes the connection node ofthe capacitor C12 and the resistor R12 have a low logic level signal. Atthis moment, the output of the inverter INV changes to a high logiclevel signal to make the OR gate output a high logic level signal (asecond pulse signal DP2) at the pulse signal output terminal 3111. Thedetection result latching circuit 3120 as illustrated in FIG. 15A storesthe detection result for a second time according to the detection resultsignal Sdr received from the detection determining circuit 3130 (asillustrated in FIG. 15A) and the pulse signal generated at the pulsesignal output terminal 3111. Next, the driving voltage VCC charges thecapacitor C12 through the resistor R12 to make the voltage on theconnection node of the capacitor C12 and the resistor R12 increase withtime to the driving voltage VCC. When the voltage on the connection nodeof the capacitor C12 and the resistor R12 increases to reach a highlogic trigger logic level, the inverter INV outputs a low logic levelsignal again to make the OR gate OG1 stop outputting the second pulsesignal DP2. The width of the second pulse signal DP2 is determined bythe capacitance value of the capacitor C12 and the resistance value ofthe resistor R12.

As those mentioned above, in certain embodiments, the detection pulsegenerating module 3110 generates two high logic level pulse signals inthe detection mode DTM, which are the first pulse signal DP1 and thesecond pulse signal DP2. These pulse signals are output from the pulsesignal output terminal 3111. Moreover, there is an interval TIV with adefined time between the first and second pulse signals DP2 (e.g., anopposite-logic signal, which may have a low logic level when the pulsesignals have a high logic level). In embodiments using the circuits asshown in FIG. 15B to implement the detection pulse generating module3110, the defined time is determined by the capacitance value of thecapacitor C11 and the resistance value of the resistor R11. In otherembodiments using digital circuits to implement the detection pulsegenerating module 3110, adjustment of the set interval TIV can beimplemented by setting the signal frequency or period or otheradjustable parameter(s) of the digital circuit of each embodiment.

From the detection mode DTM entering the LED operating mode DRM, thedetection pulse generating module 3110 does not produce the pulse signalany more, and keeps the pulse signal output terminal 3111 on a low logiclevel potential. As described herein, the LED operating mode DRM is thestage following the detection mode (e.g., following the time after thesecond pulse signal DP2 ends). The LED operating mode DRM occurs whenthe LED tube lamp is at least partly connected to a power source, suchas provided in a lamp socket. For example, the LED operating mode DRMmay occur when part of the LED tube lamp, such as only one side of theLED tube lamp, is properly connected to one side of a lamp socket, andpart of the LED tube lamp is either connected to a high impedance, suchas a person, and/or is improperly connected to the other side of thelamp socket (e.g., is misaligned so that the metal contacts in thesocket do not contact metal contacts in the LED tube lamp). The LEDoperating mode DRM may also occur when the entire LED tube lamp isproperly connected to the lamp socket.

Referring to FIG. 15C, a detection determining circuit according to somecertain embodiments is illustrated. An exemplary detection determiningcircuit 3130 includes a comparator CP11 and a resistor R14. Thecomparator CP11 may also be referred to as a first comparator CP11 andthe resistor R14 may also be referred to as a fifth resistor R14. Anegative input terminal of the comparator CP11 receives a referencelogic level signal (or a reference voltage) Vref, a positive inputterminal thereof is grounded through the resistor R14 and is alsocoupled to a switch circuit coupling terminal 3201. Referring to FIGS.15A and 15C, the signal flowing into the switch circuit 3200 from theinstallation detection terminal TE1 outputs to the switch circuitcoupling terminal 3201 to the resistor R14. When the current of thesignal passing through the resistor R14 reaches a certain level (forexample, bigger than or equal to a defined current for installation,(e.g. 2A) and this makes the voltage on the resistor R14 higher than thereference voltage Vref (referring to two end caps inserted into the lampsocket) the comparator CP11 produces a high logic level detection resultsignal Sdr and outputs it to the detection result terminal 3131. Forexample, when an LED tube lamp is correctly installed in a lamp socket,the comparator CP11 outputs a high logic level detection result signalSdr at the detection result terminal 3131, whereas the comparator CP11generates a low logic level detection result signal Sdr and outputs itto the detection result terminal 3131 when a current passing through theresistor R14 is insufficient to make the voltage on the resistor R14higher than the reference voltage Vref (referring to only one end capinserted into the lamp socket.) Therefore, in some embodiments, when theLED tube lamp is incorrectly installed in the lamp socket or one end capthereof is inserted into the lamp socket but the other one is groundedby an object such as a human body, the current will be too small to makethe comparator CP11 output a high logic level detection result signalSdr to the detection result terminal 3131.

Referring to FIG. 15D, a schematic detection result latching circuitaccording to some embodiments of the present invention is illustrated. Adetection result latching circuit 3120 includes a D flip-flop DFF, aresistor R15, and an OR gate OG2. The D flip-flop DFF may also bereferred to as a first D flip-flop DFF, the resistor R15 may also bereferred to as a fourth resistor R15, and the OR gate OG2 may also bereferred to as a second OR gate OG2. The D flip-flop DFF has a CLK inputterminal coupled to a detection result terminal 3131, and a D inputterminal coupled to a driving voltage VCC. When the detection resultterminal 3131 first outputs a low logic level detection result signalSdr, the D flip-flop DFF initially outputs a low logic level signal at aQ output terminal thereof, but the D flip-flop DFF outputs a high logiclevel signal at the Q output terminal thereof when the detection resultterminal 3131 outputs a high logic level detection result signal Sdr.The resistor R15 is coupled between the Q output terminal of the Dflip-flop DFF and a reference voltage, such as ground potential. Whenthe OR gate OG2 receives the first or second pulse signals DP1/DP2 fromthe pulse signal output terminal 3111 or receives a high logic levelsignal from the Q output terminal of the D flip-flop DFF, the OR gateOG2 outputs a high logic level detection result latching signal at adetection result latching terminal 3121. The detection pulse generatingmodule 3110 only in the detection mode DTM outputs the first and thesecond pulse signals DP1/DP2 to make the OR gate OG2 output the highlogic level detection result latching signal, and thus the D flip-flopDFF decides the detection result latching signal to be the high logiclevel or the low logic level the rest of the time, e.g., including theLED operating mode DRM after the detection mode DTM. Accordingly, whenthe detection result terminal 3131 has no high logic level detectionresult signal Sdr, the D flip-flop DFF keeps a low logic level signal atthe Q output terminal to make the detection result latching terminal3121 also keep a low logic level detection result latching signal in thedetection mode DTM. On the contrary, once the detection result terminal3131 has a high logic level detection result signal Sdr, the D flip-flopDFF outputs and keeps a high logic level signal (e.g., based on VCC) atthe Q output terminal. In this way, the detection result latchingterminal 3121 keeps a high logic level detection result latching signalin the LED operating mode DRM as well.

Referring to FIG. 15E, a schematic switch circuit according to someembodiments is illustrated. A switch circuit 3200 a includes atransistor, such as a bipolar junction transistor (BJT) M11, as being apower transistor, which has the ability of dealing with highcurrent/power and is suitable for the switch circuit. The BJT M11 mayalso be referred to as a first transistor M11. The BJT M11 has acollector coupled to an installation detection terminal TE1, a basecoupled to a detection result latching terminal 3121, and an emittercoupled to a switch circuit coupling terminal 3201. When the detectionpulse generating module 3110 produces the first and second pulse signalsDP1/DP2, the BJT M11 is in a transient conducting state. This allows thedetection determining circuit 3130 to perform the detection fordetermining the detection result latching signal to be a high logiclevel or a low logic level. When the detection result latching circuit3120 outputs a high logic level detection result latching signal at thedetection result latching terminal 3121, this means the LED tube lamp iscorrectly installed in the lamp socket, so that the BJT M11 is in theconducting state to make the installation detection terminals TE1 andTE2 conducting (i.e., make the power loop conducting). In the meantime,the driving circuit (not shown) in the power supply module starts tooperate in response to the voltage received from the power loop andgenerates the lighting control signal Slc for controlling the conductingstate of the power switch (not shown), so that the driving current canbe produced to light up the LED module. In contrast, when the detectionresult latching circuit 3120 outputs a low logic level detection resultlatching signal at the detection result latching terminal 3121 and theoutput from detection pulse generating module 3110 is a low logic level,the BJT M11 is cut-off or in the blocking state to make the installationdetection terminals TE1 and TE2 cut-off or blocking. In this case, thedriving circuit of the power supply module would not be started, so thatthe lighting control signal Slc would not be generated.

FIG. 15F is a circuit diagram of a switching circuit according to someembodiments. Compared to the embodiment of FIG. 15E where a switchingcircuit 3200 a comprises a transistor M11, the switching circuit 3200 aof FIG. 15F comprises a transistor illustrated by a MOSFET M12, andfurther includes a pulse resetting auxiliary circuit 320. In theembodiment of FIG. 19F, the pulse resetting auxiliary circuit 320 iselectrically connected to a control terminal of the transistor M12 and adetection result latching terminal 3121 of the detection result latchingcircuit 3120. The pulse resetting auxiliary circuit 320 is configured toreset signal S_(M12) provided to the control terminal of the transistorM12 under the detection mode, so as to cause a falling edge of thesignal S_(M12) to match a signal at the detection result latchingterminal 3121 under the detection mode which can be referred to as thepulse signal at the pulse signal output terminal 3111. Therefore, thepulse resetting auxiliary circuit 320 can increase the discharge speedof the signal S_(M12) under the detection mode, so that the signalS_(M12) can be pulled to a low level fast when the pulse signal ispulled to a low level, and thereby reducing the phase difference betweenthe pulse signal and the signal S_(M12) and preventing misoperation ofthe transistor M12.

Specifically, when the LED tube lamp is operating in a detection mode,the detection result latching circuit 3120 is configured to output apulse signal through a detection result latching terminal 3121 tocontrol the transistor M12 for periodically and intermittentlyconducting. Without regard to the speed of rising up and falling down ofits voltage level, i.e. assuming that the slope of both the rising upand the falling down is close to being infinite, the signal S_(M12) isapproximately a pulse signal too and may be substantially synchronouswith the signal at the detection result latching terminal 3121, with thetwo signals concurrently rising up and concurrently falling down. But inactual practice, the speed of charging (or rising up) and discharging(or falling down) of the signal S_(M12) may be significantly affected byrelevant circuit design and chosen values of device parameters of thetransistor M12. For example, if the transistor M12 has greater chosendimensions, parasitic capacitors between the control terminal and one ofthe other terminals of the transistor M12 will be greater which prolongsits charging and discharging time. Thus, considering the speed of risingup and falling down of its voltage level, the signal S_(M12) might notbe synchronous with the signal at the detection result latching terminal3121. To address this issue, in this embodiment of FIG. 15F, the pulseresetting auxiliary circuit 320 is configured to be enabled, when thedetection result latching circuit 3120 outputs a low-level signal andthe signal S_(M12) remains at a high voltage level, to further conductan additional discharge path for improving the discharge speed and thussolving the asynchronous problem.

In some embodiments, the pulse resetting auxiliary circuit 320 may berealized by a circuit structure shown in FIG. 15F, wherein the pulseresetting auxiliary circuit 320 includes a transistor M13 (illustratedby but not limited to a PNP BJT), and resistors R16 and R17. Thetransistor M13 has a control terminal electrically connected through theresistor R16 to a detection result latching terminal 3121, a firstterminal electrically connected to the control terminal of thetransistor M12, and a second terminal electrically connected through theresistor R17 to a ground terminal GND. In some embodiments, the pulseresetting auxiliary circuit 320 may further include a diode D12 andresistors R18 and R19. The diode D12 has an anode electrically connectedto the detection result latching terminal 3121, and has a cathodeelectrically connected to an end of the resistor R18, which has theother end electrically connected to the control terminal of thetransistor M12 and the first terminal of the transistor M13. And theresistor R19 is electrically connected between the control terminal ofthe transistor M12 and the ground terminal GND.

When the LED tube lamp is operating in a normal operation mode, thedetection result latching circuit 3120 is configured to output ahigh-level signal through the detection result latching terminal 3121,causing the signal S_(M12) at the control terminal of the transistor M12to have a high level to conduct the transistor M12. At this time, thetransistor M13 of the pulse resetting auxiliary circuit 320 remains at acutoff state in response to the high-level signal at the detectionresult latching terminal 3121, so the voltage level of the signalS_(M12) is not significantly affected by the pulse resetting auxiliarycircuit 320. In this case, the pulse resetting auxiliary circuit 320 isregarded as being disabled.

On the other hand, when the LED tube lamp is operating in a detectionmode, if the signal S_(M12) is substantially synchronous with, or doesnot have substantial phase difference from, the signal at the detectionresult latching terminal 3121, no matter whether the signal S_(M12) ishaving a high voltage level or low voltage level, the transistor M13 isin a reverse-biased state between its control terminal and firstterminal, causing the transistor M13 to remain in a cutoff state. But ifthe signal S_(M12) is not synchronous with, or does have substantialphase difference from, the signal at the detection result latchingterminal 3121, especially when the signal S_(M12) lags in phase behindthe signal at the detection result latching terminal 3121, the signalS_(M12) has a high voltage level and the signal at the detection resultlatching terminal 3121 has a low voltage level, causing the transistorM13 to be in a forward-biased state between its control terminal andfirst terminal. In this case, the pulse resetting auxiliary circuit 320is regarded as being enabled and the transistor M13 is caused toconduct, so that the signal S_(M12) can be discharged through adischarge path from the transistor M13 to the resistor R17 and then tothe ground terminal GND. In this manner, the speed of falling down ofthe signal S_(M12) from a high level to a low level is further improved.

Since the external driving signal Sed is an AC signal and in order toavoid the detection error resulting from the logic level of the externaldriving signal being just around zero when the detection determiningcircuit 3130 detects, the detection pulse generating module 3110generates the first and second pulse signals DP1/DP2 to let thedetection determining circuit 3130 perform two detections. So the issueof the logic level of the external driving signal being just around zeroin a single detection can be avoided. In some cases, the time differencebetween the productions of the first and second pulse signals DP1/DP2 isnot multiple times of half one cycle T of the external driving signalSed. For example, it does not correspond to the multiple phasedifferences of 180 degrees of the external driving signal Sed. In thisway, when one of the first and second pulse signals DP1/DP2 is generatedand unfortunately the external driving signal Sed is around zero, it canbe avoided that the external driving signal Sed is again around zerowhen the other pulse signal is generated.

The time difference between the productions of the first and secondpulse signals DP1/DP2, for example, an interval TIV with a defined timebetween both of them can be represented as following:

TIV=(X+Y)(T/2),

where T represents the cycle of an external driving signal Sed, X is anatural number, 0<Y<1, with Y in some embodiments in the range of0.05-0.95, and in some embodiments in the range of 0.15-0.85.

A person of ordinary skill in the relevant art of the present disclosurecan understand according to the above descriptions of embodiments thatthe method of generating two pulses or pulse signals so as to performinstallation detection is merely an exemplary embodiment of how thedetection pulse generating module operates, and that in practice thedetection pulse generating module may be configured to generate at leastone or two pulse signals so as to perform installation detection,although the present invention is not limited to any of these differentnumbers.

Furthermore, in order to avoid the installation detection moduleentering the detection mode DTM from misjudgment resulting from thelogic level of the driving voltage VCC being too small, the first pulsesignal DP1 can be set to be produced when the driving voltage VCCreaches or is higher than a defined logic level. For example, in someembodiments, the detection determining circuit 3130 works after thedriving voltage VCC reaching a high enough logic level in order toprevent the installation detection module from misjudgment due to aninsufficient logic level.

According to the examples mentioned above, when one end cap of an LEDtube lamp is inserted into a lamp socket and the other one floats orelectrically couples to a human body or other grounded object, thedetection determining circuit outputs a low logic level detection resultsignal Sdr because of high impedance. The detection result latchingcircuit stores the low logic level detection result signal Sdr based onthe pulse signal of the detection pulse generating module, making it asthe low logic level detection result latching signal, and keeps thedetection result in the LED operating mode DRM, without changing thelogic value. In this way, the switch circuit keeps cutting-off orblocking instead of conducting continually. And further, the electricshock situation can be prevented and the requirement of safety standardcan also be met. On the other hand, when two end caps of the LED tubelamp are correctly inserted into the lamp socket (e.g., at the timepointtd), the detection determining circuit outputs a high logic leveldetection result signal Sdr because the impedance of the circuit for theLED tube lamp itself is small. The detection result latching circuitstores the high logic level detection result signal Sdr based on thepulse signal of the detection pulse generating module, making it as thehigh logic level detection result latching signal, and keeps thedetection result in the LED operating mode DRM. So the switch circuitkeeps conducting to make the LED tube lamp work normally in the LEDoperating mode DRM.

In some embodiments, when one end cap of the LED tube lamp is insertedinto the lamp socket and the other one floats or electrically couples toa human body, the detection determining circuit outputs a low logiclevel detection result signal Sdr to the detection result latchingcircuit, and then the detection pulse generating module outputs a lowlogic level signal to the detection result latching circuit to make thedetection result latching circuit output a low logic level detectionresult latching signal to make the switch circuit cutting-off orblocking. As such, the switch circuit blocking makes the installationdetection terminals, e.g. the first and second installation detectionterminals, blocking. As a result, the LED tube lamp is in non-conductingor blocking state.

However, in some embodiments, when two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal Sdr to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level detection result latching signal tomake the switch circuit conducting. As such, the switch circuitconducting makes the installation detection terminals, e.g. the firstand second installation detection terminals, conducting. As a result,the LED tube lamp operates in a conducting state.

Thus, according to the operation of the installation detection module, afirst circuit, upon connection of at least one end of the LED tube lampto a lamp socket, generates and outputs two pulses, each having a pulsewidth, with a time period between the pulses. The first circuit mayinclude various of the elements described above configured to output thepulses to a base of a transistor (e.g., a BJT transistor) that serves asa switch. The pulses occur during a detection mode DTM for detectingwhether the LED tube lamp is properly connected to a lamp socket. Thetiming of the pulses may be controlled based on the timing of variousparts of the first circuit changing from high to low logic levels, orvice versa.

The pulses can be timed such that, during that detection mode DTM time,if the LED tube lamp is properly connected to the lamp socket (e.g.,both ends of the LED tube lamp are correctly connected to conductiveterminals of the lamp socket), at least one of the pulse signals occurswhen an AC current from an external driving signal is at a non-zerolevel. For example, the pulse signals can occur at intervals TIV thatare different from half of the period of the AC signal. For example,respective start points or mid points of the pulse signals, or a timebetween an end of the first pulse signal DP1 and a beginning of thesecond pulse signal DP2 may be separated by an amount of time that isdifferent from half of the period of the AC signal (e.g., it may bebetween 0.05 and 0.95 percent of a multiple of half of the period of theAC signal). During a pulse that occurs when the AC signal is at anon-zero level, a switch that receives the AC signal at the non-zerolevel may be turned on, causing a latch circuit to change states suchthat the switch remains permanently on so long as the LED tube lampremains properly connected to the lamp socket. For example, the switchmay be configured to turn on when each pulse is output from the firstcircuit. The latch circuit may be configured to change state only whenthe switch is on and the current output from the switch is above athreshold value, which may indicate a proper connection to a lightsocket. As a result, the LED tube lamp operates in a conducting state.

Accordingly, under the process of installing the LED tube lamp by auser, once the LED tube lamp is powered up (no matter whether the LEDtube lamp is lighted up or not), the installation detection module ofthe LED tube lamp generates the pulse for detecting the installationstate or the occurrence of electric shock before continuously conductingthe power loop, so that the driving current is conducted through thepower loop to drive the LED module after confirming the LED tube lamp iscorrectly installed or is not touched by the user. Therefore, the LEDtube lamp would not be lighted up until the first pulse being generated,which means the power loop would not be conducted or the current on thepower loop would be limited to less than 5 mA/MIU. In practicalapplication, the period from the timepoint of the LED tube lamp beingpowered up to the timepoint of the first pulse being generated issubstantially not less than 100 ms. For example, the LED tube lampprovided with the installation detection module of the presentembodiment does not emit light until at least 100 ms after beinginstalled and powered up. In some embodiments, since the installationdetection module continuously generates the pulses before determiningwhether the installation state is correct or determining that the userdoes not touch the LED tube lamp, the LED tube lamp will be lighted upafter at least the interval TIV (i.e., after the second pulse isgenerated) if the LED tube lamp is not lighted up after the first pulseis generated. In this example, if the LED tube lamp is not lighted upafter 100 ms, the LED tube lamp does not emit light in at least 100+TIVms as well. It should be noted that such an expression “the LED tubelamp is powered up” refers to the fact that an external power source(such as the AC power line) is applied to the LED tube lamp, with apower loop of the LED tube lamp being electrically connected to a groundlevel so as to produce a voltage difference on the power loop. That thepowered-up LED tube lamp is properly/correctly installed means theexternal power source is applied to the LED tube lamp and the LED tubelamp is electrically connected to the ground level through a ground lineof the lamp fixture. And that the powered-up LED tube lamp isimproperly/incorrectly installed refers to that the external powersource is applied to the LED tube lamp and the LED tube lamp iselectrically connected to the ground level not only through a groundline of the lamp fixture but also through a human body or other objectof impedance, which means that in the state of beingimproperly/incorrectly installed an unexpected object or body ofimpedance happens to be serially connected on a current path in thepower loop.

It should be noted that, the LED tube lamp being powered up refers tothe external driving signal being applied to at least one pin of the LEDtube lamp and causing a current flowing through the LED tube lamp, inwhich the current can be the driving current or the leakage current.

On the other hand, if both pulses occur when an external driving signalat the LED tube lamp has a near-zero current level, or a current levelbelow a particular threshold, then the state of the latch circuit is notchanged, and so the switch is only on during the two pulses, but thenremains permanently off after the pulses and after the detection mode isover. For example, the latch circuit can be configured to remain in itspresent state if the current output from the switch is below thethreshold value. In this manner, the LED tube lamp remains in anon-conducting state, which prevents electric shock, even though part ofthe LED tube lamp is connected to an electrical power source.

It is worth noting that according to certain embodiments, the pulsewidth of the pulse signal generated by the detection pulse generatingmodule is between 1 μs to 1 ms, and it is used to make the switchcircuit conducting for a short period when the LED tube lamp conductsinstantaneously. In an exemplary embodiment, the pulse width of thepulse signal is between 10 μs to 1 ms. In another exemplary embodiment,the pulse width of the pulse signal is between 10 μs to 30 μs. Inanother exemplary embodiment, the pulse width of the pulse signalDP1/DP2 is in a broader range between 200 μs and 400 μs. In anotherexemplary embodiment, the pulse width of the pulse signal DP1/DP2 iswithin a range of between plus and minus 15% of 20 μs, 35 μs, or 45 μs.And in another exemplary embodiment, the pulse width of the pulse signalDP1/DP2 is within a range of between plus and minus 15% of 300 μs.

According to some embodiments, the pulse or pulse signal means amomentary occurrence of abrupt variation of a signal of voltage orcurrent in a continual period of the signal, that is, in a short periodof time the signal suddenly abruptly varies and then quickly returns toan initial value before variation. Thus the pulse signal may be a signalof voltage or current that varies or transitions from a low level to ahigh level and after a short time at the high level returns to the lowlevel, or that varies or transitions from a high level to a low leveland then returns to the high level, while the invention is not limitedto any of these options. Such an expression “momentary occurrence ofsignal variation” corresponds to a period of time not sufficient for theLED tube lamp as a unit to change its state of operation and duringwhich period the momentary signal variation is unlikely to cause anelectric shock hazard on a touching human body. For example, when usingthe pulse signal DP1/DP2 to cause conduction of the switch circuit3200/3200 a, the duration of the conduction of the switch circuit3200/3200 a is so short as not to light up the LED module, and is soshort as to cause an effective current on the power loop to not exceed arated current upper limit (5 MIU). And the “abrupt variation of asignal” refers to an extent of variation of the pulse or pulse signalsufficient to cause an electrical element receiving it to respondthereto and then change the element's operation state. For example, whenthe switch circuit 3200/3200 a receives the pulse signal DP1/DP2, theswitch circuit 3200/3200 a conducts or is cut off in response toswitching of the signal level of the pulse signal DP1/DP2.

In some embodiments, a pulse current is generated to pass through thedetection determining circuit for detecting and determining. Since thepulse is for a short time and not for a long time, the electric shocksituation will not occur. Furthermore, the detection result latchingcircuit also keeps the detection result during the LED operating modeDRM (e.g., the LED operating mode DRM being the period after thedetection mode DTM and during which part of the LED tube lamp is stillconnected to a power source), and no longer changes the detection resultstored previously complying with the circuit state changing. A situationresulting from changing the detection result can thus be avoided. Insome embodiments, the installation detection module, such as the switchcircuit, the detection pulse generating module, the detection resultlatching circuit, and the detection determining circuit, could beintegrated into a chip and then embedded in circuits for saving thecircuit cost and layout space.

In addition, although the detection pulse generating module 3110generates two pulse signals DP1 and DP2 for example, the detection pulsegenerating module 3110 of the present invention is not limited thereto.The detection pulse generating module 3110 is a circuit capable ofgenerating a single pulse or plural pulses (greater than two pulses).

For an embodiment of the detection pulse generating module 3110generating only one pulse or pulse signal, a simple circuitconfiguration using an RC circuit in combination with active electricalelement(s) (having internal power source) can be used to implement thegeneration/issuance of only one pulse. For example, in some embodiments,the detection pulse generating module 3110 merely includes the capacitorC11, resistor R11 and buffer BF1. Under such configuration, thedetection pulse generating module can only generate a single pulsesignal DP1.

Under an embodiment of the detection pulse generating module 3110generating a plurality of pulse signals, in some embodiments, thedetection pulse generating module 3110 further includes a reset circuit(not shown). The reset circuit may reset the operation state of thecircuits in the detection pulse generating module 3110 after the firstpulse signal DP1 and/or the second pulse signal DP2 being generated, sothat the detection pulse generating module 3110 can generate the firstpulse signal DP1 and/or the second pulse signal DP2 again after a while.The generating of the plurality of pulse signals at intervals of a fixedperiod TIV may be for example generating a pulse signal every 20 ms to 2s (that is, 20 ms TIV 2 s). In one embodiment, the fixed period TIV isbetween 500 ms and 2 s. In another embodiment, the fixed period TIV isin a range of between plus and minus 15% of 75 ms. In still anotherembodiment, the fixed period TIV is in a range of between plus and minus15% of 45 ms. In still another embodiment, the fixed period TIV is in arange of between plus and minus 15% of 30 ms. And the generating of theplurality of pulse signals at intervals of a random period TIV may befor example performed by choosing a random value in a range of between0.5 s and 2 s as the random period TIV between every two consecutivegenerated pulse signals.

In particular, the time and frequency for the detection pulse generatingmodule 3110 to generate a pulse signal to perform installation detectionmay be set or adjusted taking account of effects of a detection currentunder a detection stage on a normal human body touching or exposed tothe detection current. In general, as long as the magnitude and durationof the detection current which is flowing through the human body conformto limiting requirements of relevant standards, the detection currentflowing through the human body will not cause the human body to feel orexperience an electric shock hazard and will not endanger the safety ofthe human body. The magnitude and the duration of the detection currentshould be in inverse relation so as to conform to limiting requirementsof relevant standards to avoid the electric shock hazard. For example,under the requirement that the detection current flowing through thehuman body does not endanger the safety of the human body, the greaterthe magnitude of the detection current, the shorter the duration of thedetection current flowing through the human body should be; inversely,if the magnitude of the detection current is very small, a rather longduration of the detection current flowing through the human body stillwould or could not endanger the safety of the human body. Therefore,whether the detection current flowing through the human body endangersthe safety of the human body or not is based on or determined by theamount of electric charge per unit time, or electric power, from thedetection current and applied to or received by the human body, but notmerely determined by the amount of electric charge received by the humanbody.

In some embodiments, the detection pulse generating module 3110 isconfigured to generate pulses or pulse signals for performinginstallation detection, only during a specific detection period, andoutside the period to stop generating a pulse signal for installationdetection, in order to prevent the detection current from causingelectric shock on the touching human body. FIG. 41D is a signal waveformdiagram of the detection current according to some embodiments, whereinthe horizontal axis is the time axis (denoted by t) and the verticalaxis represents value of the detection current (denoted by I). Referringto FIG. 41D, within a detection stage, the detection pulse generatingmodule 3110 generates pulse signals for performing installationdetection, during a specific detection period, to cause conduction of adetection path or a power loop in the LED tube lamp, wherein details ofhow the pulse width of each pulse and the interval between twoconsecutive pulses are set are referred to other described relevantembodiments elsewhere herein. Since the detection path or power loop isbeing conducted, a detection current signal Iin on the detection path orpower loop, whose value may be obtained by measuring an input current tothe power supply module of the LED tube lamp, includes a current pulseIdp generated corresponding to the time that each of the pulse signalsis generated, and a detection determining circuit 3130 judges whetherthe LED tube lamp is correctly/properly installed in a lamp socket bymeasuring the value of the current pulse Idp. After the detection periodTw shown in FIG. 41D, the detection pulse generating module 3110 stopsgenerating a pulse signal for installation detection, to cause thedetection path or the power loop to be in a cutoff state. Viewing thedetection current signal Iin broadly along the time axis, the detectionpulse generating module 3110 generates a group of current pulses DPgduring the detection period Tw, and judges whether the LED tube lamp iscorrectly/properly installed in a lamp socket by performing installationdetection using the group of current pulses DPg. For example, in theembodiment of FIG. 41D, the detection pulse generating module 3110generates current pulses Idp only during the detection period Tw,wherein the detection period Tw may be set in a range of between 0.5 sand 2 s and including every two-digit decimal number between andincluding the 0.5 s and 2 s, such as 0.51, 0.52, 0.53, . . . 0.60, 0.61,0.62, . . . , 1.97, 1.98, 1.99, and 2, all in seconds, but this presentinvention is not limited to this range embodiment. And it is noted thatby appropriately choosing a detection period Tw, it can be achieved thatperforming installation detection using the group of current pulses DPgdoes not generate excessive electrical power by the detection currentthat will endanger the touching human body, so the electric shockprotection can be achieved.

With respect to circuit design, the way of the detection pulsegenerating module 3110 generating detection current pulses Idp onlyduring the detection period Tw can be implemented by various differentcircuit embodiments. For example, in one embodiment, a detection pulsegenerating module 3110 is implemented by a pulse generating circuit (asillustrated in FIG. 15B or FIG. 16B) along with a timing circuit (notillustrated herein), wherein the timing circuit may be configured to,upon detecting a period, output a signal to cause the pulse generatingcircuit to stop generating the pulse(s). In another embodiment, adetection pulse generating module 3110 is implemented by a pulsegenerating module (as illustrated in FIG. 15B or FIG. 16B) along with ashielding/isolation circuit (not illustrated herein), wherein theshielding/isolation circuit may be configured to, after a predefinedtime, shield or prevent the detection pulse(s) from being generated oroutput by the pulse generating circuit, by any of a number of ways suchas pulling (the voltage of) the output terminal of the detection pulsegenerating module to ground. Under the configuration with ashielding/isolation circuit, the shielding/isolation circuit may beimplemented by a simple circuit such as an RC circuit, without the needto modify an original circuit design of the pulse generating circuit.

In some embodiments, the detection pulse generating module 3110 isconfigured to generate pulses or pulse signals for performinginstallation detection, at intervals each of which intervals between twoconsecutive pulses is set greater than or equal to a safety value, inorder to prevent the detection current from causing electric shock onthe touching human body. FIG. 41E is a signal waveform diagram of thedetection current according to some exemplary embodiment. Referring toFIG. 41E, within a detection stage, the detection pulse generatingmodule 3110 generates pulses for performing installation detection, atintervals each of which intervals between two consecutive pulses is setat TIVs (the ‘s’ denoting second) greater than a specific safety valuesuch as 1 second, to cause conduction of a detection path or a powerloop in the LED tube lamp, wherein details of how the pulse width ofeach pulse is set are referred to other described relevant embodimentselsewhere herein. Since the detection path or power loop is beingconducted, a detection current signal Iin on the detection path or powerloop, whose value may be obtained by measuring an input current to thepower supply module of the LED tube lamp, includes a current pulse Idpgenerated corresponding to the time that each of the pulse signals isgenerated, and a detection determining circuit 3130 judges whether theLED tube lamp is correctly/properly installed in a lamp socket bymeasuring the value of the current pulse Idp.

In some embodiments, the detection pulse generating module 3110 isconfigured to generate a group of pulses or pulse signals for performinginstallation detection, each group generated during a specific detectionperiod Tw, periodically at intervals each of which intervals beinggreater than or equal to a specific safety value, in order to preventthe detection current from causing electric shock on the touching humanbody. FIG. 41F is a signal waveform diagram of the detection currentaccording to a third embodiment. Referring to FIG. 41F, within adetection stage, the detection pulse generating module 3110 generates agroup of pulse signals for performing installation detection, during afirst detection period Tw, to cause conduction of a detection path or apower loop in the LED tube lamp, wherein details of how the pulse widthof each pulse and the interval between two consecutive pulses are setare referred to other described relevant embodiments herein. Since thedetection path or power loop is being conducted, a detection currentsignal Iin on the detection path or power loop includes a current pulseIdp generated corresponding to the time that each of the group of thepulse signals is generated, resulting in a first current pulse groupDPg1 of the generated current pulses Idp for or during the firstdetection period Tw. After the first detection period Tw, during a setperiod TIV such as a period greater than or equal to 1 second, thedetection pulse generating module 3110 stops generating a pulse signalfor installation detection, to cause the detection path or the powerloop to be in a cutoff state; and then the detection pulse generatingmodule 3110 continues to generate again a group of pulse signals forperforming installation detection, only upon entering into the next or asecond detection period Tw. Similar to the operations and the waveformof the detection current signal Iin during the first detection periodTw, a second current pulse group DPg2 of generated current pulses Idpand a third current pulse group DPg3 of generated current pulses Idp areproduced on the detection current signal Iin during the second detectionperiod Tw and the third detection period Tw, respectively. And in thisprocess, a detection determining circuit 3130 judges whether the LEDtube lamp is correctly/properly installed in a lamp socket by measuringthe value(s) of each of the first current pulse group DPg1, the secondcurrent pulse group DPg2, the third current pulse group DPg3, etc.

It's noted that in practice the magnitude of current of the currentpulse Idp is related to or depends on impedance (such as resistance) onthe detection path or power loop. Therefore when designing a detectionpulse generating module 3110, the format of the output detection pulsemay be designed according to the adopted choice and configuration of thedetection path or power loop.

In some embodiments, the time point for generating the pulse signalDP1/DP2 can be determined by sampling the external driving signal/ACdriving signal and the pulse width of the pulse signal DP1/DP2 isdesigned to be fixed. For example, the detection pulse generating moduleincludes a sampling circuit and a pulse generating circuit. The samplingcircuit outputs a pulse generating signal to the pulse generatingcircuit when the AC voltage of the external driving signal rises orfalls to exceed a reference voltage, so that the pulse generatingcircuit outputs a pulse signal when receiving the pulse generatingsignal.

As discussed in the above examples, in some embodiments, an LED tubelamp includes an installation detection circuit comprising a firstcircuit configured to output two pulse signals, the first pulse signalDP1 output at a first time and the second pulse signal DP2 output at asecond time after the first time, and a switch configured to receive anLED driving signal and to receive the two pulse signals, wherein the twopulse signals control turning on and off of the switch. The installationdetection circuit may be configured to, during a detection mode DTM,detect during each of the two pulse signals whether the LED tube lamp isproperly connected to a lamp socket. When it is not detected duringeither pulse signal that the LED tube lamp is properly connected to thelamp socket, the switch may remain in an off state after the detectionmode DTM. When it is detected during at least one of the pulse signalsthat the LED tube lamp is properly connected to the lamp socket, theswitch may remain in an on state after the detection mode DTM. The twopulse signals may occur such that they are separated by a time differentfrom a multiple of half of a period of the LED driving signal, and suchthat at least one of them does not occur when the LED driving signal hasa current value of substantially zero. It should be noted that althougha circuit for producing two pulse signals is described, the disclosureis not intended to be limiting as such. For example, a circuit may beimplemented such that a plurality of pulse signals may occur, wherein atleast two of the plurality of pulse signals are separated by a timedifferent from a multiple of half of a period of the LED driving signal,and such that at least one of the plurality of pulse signals does notoccur when the LED driving signal has a current value of substantiallyzero.

Referring to FIG. 16A, an installation detection module according to anexemplary embodiment is illustrated. The installation detection module3000 b includes a detection pulse generating module 3210 (which may alsobe referred to as a detection pulse generating circuit or a firstcircuit), a detection result latching circuit 3220 (which may also bereferred to as a second circuit), a switch circuit 3200 b (which mayalso be referred to as a third circuit), and a detection determiningcircuit 3230 (which may also be referred to as a fourth circuit). Insome embodiments, the first circuit 3210, the second circuit 3220 andthe fourth circuit 3230 can be referred to a detection circuit or anelectric shock detection/protection circuit, which is configured tocontrol the switching state of the switch circuit/third circuit 3200 b.

FIG. 41B is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. The installation detectionoperation is described further in accordance with FIG. 41B. Thedetection pulse generating module 3210 is coupled (e.g., electricallyconnected) to the detection result latching circuit 3220 via a path3211, and is configured to generate a control signal Sc having at leastone pulse signal DP. A path as described herein may include a conductiveline connecting between two components, circuits, or modules, and mayinclude opposite ends of the conductive line connected to the respectivecomponents, circuits or modules. The detection result latching circuit3220 is coupled (e.g., electrically connected) to the switch circuit3200 b via a path 3221, and is configured to receive and output thecontrol signal Sc from the detection pulse generating module 3210. Theswitch circuit 3200 b is coupled (e.g., electrically connected) to oneend (e.g., a first installation detection terminal TE1) of a power loopof an LED tube lamp and the detection determining circuit 3230, and isconfigured to receive the control signal Sc output from the detectionresult latching circuit 3220, and configured to conduct (or turn on)during the control signal Sc so as to cause the power loop of the LEDtube lamp to be conducting. The detection determining circuit 3230 iscoupled (e.g., electrically connected) to the switch circuit 3200 b, theother end (e.g., a second installation detection terminal TE2) of thepower loop of the LED tube lamp and the detection result latchingcircuit 3220, and is configured to detect at least one sample signal Sspon the power loop when the switch circuit 3200 b and the power loop areconductive, so as to determine an installation state between the LEDtube lamp and a lamp socket. The power loop of the present embodimentcan be regarded as a detection path of the installation detectionmodule. The detection determining circuit 3230 is further configured totransmit detection result(s) to the detection result latching circuit3220 for next control. In some embodiments, the detection pulsegenerating module 3210 is further coupled (e.g., electrically connected)to the output of the detection result latching circuit 3220 to controlthe time of the pulse signal DP.

In some embodiments, one end of a first path 3201 is coupled to a firstnode of the detection determining circuit 3230 and the opposite end ofthe first path 3201 is coupled to a first node of the switch circuit3200. In some embodiments, a second node of the detection determiningcircuit 3230 is coupled to the second installation detection terminalTE2 of the power loop and a second node of the switch circuit 3200 iscoupled to the first installation detection terminal TE1 of the powerloop. In some embodiments, one end of a second path 3231 is coupled to athird node of the detection determining circuit 3230 and the oppositeend of the second path 3231 is coupled to a first node of the detectionresult latching circuit 3220, one end of a third path 3211 is coupled toa second node of the detection result latching circuit 3220 and theopposite end of the third path 3211 is coupled to a first node of thedetection pulse generating circuit 3210. In some embodiments, one end ofa fourth path 3221 is coupled to a third node of the switch circuit 3200and the opposite end of the fourth path 3221 is coupled to a third nodeof the detection result latching circuit 3220. In some embodiments, thefourth path 3221 is also coupled to a second node of the detection pulsegenerating circuit 3210.

In some embodiments, the detection determining circuit 3230 isconfigured for detecting a signal between the first installationdetection terminal TE1 and the second installation detection terminalTE2 through the first path 3201 and the switch circuit 3200. Forexample, because of the above configuration, the detection determiningcircuit 3230 is capable of detecting and determining whether a currentpassing through the first installation detection terminal TE1 and thesecond installation detection terminal TE2 is below or above apredetermined current value and transmitting or providing a detectionresult signal Sdr to the detection result latching circuit 3220 via thesecond path 3231.

In some embodiments, the detection pulse generating circuit 3210, alsoreferred to generally as a pulse generating circuit, generates a pulsesignal DP through the detection result latching circuit 3220 to make theswitch circuit 3200 remain in a conducting state during the pulsesignal. For example, the pulse signal DP generated by the detectionpulse generating circuit 3210 controls turning on the switch circuit3200 which is coupled to the detection pulse generating circuit 3210. Asa result of maintaining a conducting state of the switch circuit 3200,the power loop of the LED tube lamp between the installation detectionterminals TE1 and TE2 is also maintained in a conducting state. Thedetection determining circuit 3230 detects a sample signal Ssp on thepower loop and generates a signal based on a detection result to informthe detection result latching circuit 3220 of a time point for latching(storing) the detection result received by the detection result latchingcircuit 3220 from the detection determining circuit 3230. For example,the detection determining circuit 3230 may be a circuit configured togenerate a signal that causes a latching circuit, such as the detectionresult latching circuit 3220 to enter and remain in a state thatcorresponds to one of a conducting state (e.g., “on” state) and acut-off state for the LED tube lamp. The detection result latchingcircuit 3220 stores the detection result according to the detectionresult signal Sdr (or detection result signal Sdr and pulse signalDP1/DP2), and transmits or provides the detection result to the switchcircuit 3200 coupled to the third node of the detection result latchingcircuit 3220 via the fourth path 3221. The switch circuit 3200 receivesthe detection result transmitted from the detection result latchingcircuit 3220 via the third node of the switch circuit 3200 and controlsthe state between conducting or cut off between the installationdetection terminals TE1 and TE2 according to the detection result. Forexample, when the detection determining circuit 3230 detects during thepulse signal DP that the LED tube lamp is not properly installed in thelamp socket, the pulse signal DP controls the switch circuit 3200 toremain in an off state to cause a power loop of the LED tube lamp to beopen, and when the detection determining circuit 3230 detects during thepulse signal DP that the LED tube lamp is properly installed in the lampsocket, the pulse signal DP controls the switch circuit 3200 to remainin a conducting state to cause the power loop of the LED tube lamp tomaintain a conducting state.

In some embodiments, the installation detection module 3000 b furtherincludes an emergency control module 3240, whose configurations andoperations are similar to those of the described emergency controlmodule 3140 above and thus are not repeatedly described again here.

In some embodiments, the detection pulse generating module 3210,detection determining circuit 3230, detection result latching circuit3220, and the switching circuit 3200 of the installation detectionmodule 3000 b comprise or are implemented by, but are not limited to,circuit structures of FIGS. 16B-16E respectively, which FIGS. 16B-16Eare circuit structure diagrams of respective circuits and module of aninstallation detection module 3000 b according to a second embodiment.Descriptions of the circuit embodiments of FIGS. 16B-16E are presentedbelow.

Referring to FIG. 16B, a detection pulse generating module according toan exemplary embodiment is illustrated. The detection pulse generatingmodule 3210 includes: a resistor R21 (which also may be referred to as asixth resistor), a capacitor C21 (which also may be referred to as afourth capacitor), a Schmitt trigger STRG, a resistor R22 (which alsomay be referred to as a seventh resistor), a transistor M21 (which alsomay be referred to as a second transistor), and a resistor R23 (whichalso may be referred to as an eighth resistor).

In some embodiments, one end of the resistor R21 is connected to adriving signal, for example, VCC, and the other end of the resistor R21is connected to one end of the capacitor C21. The other end of thecapacitor C21 is connected to a ground node. In some embodiments, theSchmitt trigger STRG has an input end and an output end, the input endconnected to a connection node of the resistor R21 and the capacitorC21, the output end connected to the detection result latching circuit3220 via the third path 3211 (FIG. 16A). In some embodiments, one end ofthe resistor R22 is connected to the connection node of the resistor R21and the capacitor C21 and the other end of the resistor R22 is connectedto a collector of the transistor M21. An emitter of the transistor M21is connected to a ground node. In some embodiments, one end of theresistor R23 is connected to a base of the transistor M21 and the otherend of the resistor R23 is connected to the detection result latchingcircuit 3220 (FIG. 16A) and the switch circuit 3200 b (FIG. 16A) via thefourth path 3221. In certain embodiments, the detection pulse generatingmodule 3210 further includes: a Zener diode ZD1, having an anode and acathode, the anode connected to the other end of the capacitor C21 tothe ground, the cathode connected to the end of the capacitor C21 (theconnection node of the resistor R21 and the capacitor C21). Thedetection pulse generating modules 3110 and 3210 in the embodiments ofFIG. 15B and FIG. 16B are merely examples, and in practice specificoperations of a detection pulse generating circuit may be performedbased on configured functional modules in an embodiment of FIG. 33, andthus will be described in detail below with reference to FIG. 33.

Referring to FIG. 16C, a detection determining circuit according to anexemplary embodiment is illustrated. The detection determining circuit3230 includes: a resistor R24 (which also may be referred to as a ninthresistor), one end of the resistor R24 connected to the emitter of thetransistor M22 (FIG. 16E), the other end of the resistor R24 connectedto the other end of the power loop, such as the second installationdetection terminal TE2; a diode D21 (which also may be referred to as asecond diode), having an anode and a cathode, the anode connected to anend of the resistor STRG that is not connected to a ground node; acomparator CP21 (which also may be referred to as a second comparator),having a first input end, a second input end, and an output end; acomparator CP22 (which also may be referred to as a third comparator),having a first input end, a second input end, and an output end; aresistor R25 (which also may be referred to as a tenth resistor); aresistor R26 (which also may be referred to as an eleventh resistor);and a capacitor C22 (which also may be referred to as a fifthcapacitor).

In some embodiments, the first input end of the comparator CP21 isconnected to a predefined signal, for example, a reference voltage,Vref=1.3V, but the reference voltage value is not limited thereto, thesecond input end of the comparator CP21 is connected to the cathode ofthe diode D21, and the output end of the comparator CP21 is connected tothe clock input end of the D flip-flop DFF (FIG. 16D). In someembodiments, the first input end of the comparator CP22 is connected tothe cathode of the diode D21, the second input end of the comparatorCP22 is connected to another predefined signal, for example, a referencevoltage, Vref=0.3V, but the reference voltage value is not limitedthereto, and the output end of the comparator CP22 is connected to theclock input end of the D flip-flop DFF (FIG. 16D). In some embodiments,one end of the resistor R25 is connected to the driving signal mentionedabove (e.g., VCC) and the other end of the resistor R25 is connected tothe second input end of the comparator CP21 and one end of the resistorR26 that is not connected to a ground node and the other end of theresistor R26 is connected to the ground node. In some embodiments, thecapacitor C22 is connected to the resistor R26 in parallel. In certainembodiments, the diode D21, the comparator CP22, the resistors R25 andR26, and the capacitor C22 may be omitted, and the second input end ofthe comparator CP21 may be directly connected to the end of the resistorR24 (e.g., the end of the resistor R24 that is not connected to theground node) when the diode D21 is omitted. In certain embodiments, theresistor R24 may include two resistors connected in parallel based onthe consideration of power consumption having an equivalent resistancevalue ranging from about 0.1 ohm to about 5 ohm.

Referring to FIG. 16D, a detection result latching circuit according toan exemplary embodiment is illustrated. The detection result latchingcircuit 3220 includes: a D flip-flop DFF (which also may be referred toas a second D flip-flop), having a data input end D, a clock input endCLK, and an output end Q, the data input end D connected to the drivingsignal mentioned above (e.g., VCC), the clock input end CLK connected tothe detection determining circuit 3230 (FIG. 16C); and an OR gate OG(which also may be referred to as a third OR gate), having a first inputend, a second input end, and an output end, the first input endconnected to the output end of the Schmitt trigger STRG (FIG. 16B), thesecond input end connected to the output end Q of the D flip-flop DFF,the output end of the OR gate OG connected to the other end of theresistor R23 (FIG. 16B) and the switch circuit 3200 (FIG. 16A).

Referring to FIG. 16E, a switch circuit according to an exemplaryembodiment is illustrated. The switch circuit 3200 includes: atransistor M22 (which also may be referred to as a third transistor),having a base, a collector, and an emitter, the base connected to theoutput of the OR gate OG via the fourth path 3221 (FIG. 16D), thecollector connected to one end of the power loop, such as the firstinstallation detection terminal TE1, the emitter connected to thedetection determining circuit 3230 (FIG. 16A). In some embodiments, thetransistor M22 may be replaced by other equivalently electronic parts,e.g., a MOSFET.

In some embodiments, some parts of the installation detection module maybe integrated into an integrated circuit (IC) in order to providereduced circuit layout space resulting in reduced manufacturing cost ofthe circuit. For example, the Schmitt trigger STRG of the detectionpulse generating module 3210, the detection result latching circuit3220, and the two comparators CP21 and CP22 of the detection determiningcircuit 3230 may be integrated into an IC, but the disclosure is notlimited thereto.

An operation of the installation detection module will be described inmore detail according to some example embodiments. In one exemplaryembodiment, the capacitor voltage may not mutate; the voltage of thecapacitor in the power loop of the LED tube lamp before the power loopis conductive is zero and the capacitor's transient response may appearto have a short-circuit condition; when the LED tube lamp is correctlyinstalled to the lamp socket, the power loop of the LED tube lamp in atransient response may have a smaller current-limiting resistance and abigger peak current; and when the LED tube lamp is incorrectly installedto the lamp socket, the power loop of the LED tube lamp in transientresponse may have a bigger current-limiting resistance and a smallerpeak current. This embodiment may also meet the UL standard to make theleakage current of the LED tube lamp less than 5 MIU (MeasurementIndication Unit), in which the unit “MIU” is defined by. The followingtable illustrates the current comparison in a case when the LED tubelamp works normally (e.g., when the two end caps of the LED tube lampare correctly installed to the lamp socket) and in a case when the LEDtube lamp is incorrectly installed to the lamp socket (e.g., when oneend cap of the LED tube lamp is installed to the lamp socket but theother one is touched by a human body).

Correct installation Incorrect installation Maximum transient current$\begin{matrix}{i_{{pk}\_\max} = {\frac{V_{{in}\_{pk}}}{R_{fuse} + 500} =}} \\{\frac{305 \times 1.414}{10 + 500} = {845\mspace{14mu}{mA}}}\end{matrix}$ Minimum transient current $\begin{matrix}{i_{{pk}\_\min} = {\frac{\Delta\; V_{in}}{R_{fuse}} =}} \\{\frac{50}{10} = {5A}}\end{matrix}$

As illustrated in the above table, in the part of the denominator:R_(fuse) represents the resistance of the fuse of the LED tube lamp. Forexample, 10 ohm may be used, but the disclosure is not limited thereto,as resistance value for R_(fuse) in calculating the minimum transientcurrent i_(pk_min) and 510 ohm may be used as resistance value forR_(fuse) in calculating the maximum transient current i_(pk_max) (anadditional 500 ohms is used to emulate the conductive resistance ofhuman body in transient response). In the part of the numerator: maximumvoltage from the root-mean-square voltage (Vmax=Vrms*1.414=305*1.414) isused in calculating the maximum transient current i_(pk_max) and minimumvoltage difference, for example, 50V (but the disclosure is not limitedthereto) is used in calculating the minimum transient currenti_(pk_min). Accordingly, when the LED tube lamp is correctly installedto the lamp socket (e.g., when two end caps of the LED tube lamp areinstalled to the lamp socket correctly) and works normally, its minimumtransient current is 5 A. But, when the LED tube lamp is incorrectlyinstalled to the lamp socket (e.g., when one end cap is installed to thelamp socket but the other one is touched by human body), its maximumtransient current is only 845 mA. Therefore, certain examples of thedisclosed embodiments use the current which passes transient responseand flows through the capacitor in the LED power loop, such as thecapacitor of the filtering circuit, to detect and determine theinstallation state between the LED tube lamp and the lamp socket. Forexample, such embodiments may detect whether the LED tube lamp iscorrectly installed to the lamp socket. Certain examples of thedisclosed embodiments further provide a protection mechanism to protectthe user from electric shock caused by touching the conductive part ofthe LED tube lamp which is incorrectly installed to the lamp socket. Theembodiments mentioned above are used to illustrate certain aspects ofthe disclosed invention but the disclosure is not limited thereto.

Further, referring to FIG. 16A again, in some embodiments, when an LEDtube lamp is being installed to a lamp socket, after a period (e.g., theperiod utilized to determine the cycle of a pulse signal), the detectionpulse generating module 3210 outputs a first high level voltage risingfrom a first low level voltage to the detection result latching circuit3220 through a path 3211 (also referred to as a third path). Thedetection result latching circuit 3220 receives the first high levelvoltage, and then simultaneously outputs a second high level voltage tothe switch circuit 3200 and the detection pulse generating module 3210through a path 3221 (also referred to as a fourth path). In someembodiments, when the switch circuit 3200 receives the second high levelvoltage, the switch circuit 3200 conducts to cause the power loop of theLED tube lamp to be conducting as well. In this exemplary embodiment,the power loop at least includes the first installation detectionterminal TE1, the switch circuit 3200, the path 3201 (also referred toas a first path), the detection determining circuit 3230, and the secondinstallation detection terminal TE2. In the meantime, the detectionpulse generating module 3210 receives the second high level voltage fromthe detection result latching circuit 3220, and after a period (e.g.,the period utilized to determine the width (or period) of pulse signal),its output from the first high level voltage falls back to the first lowlevel voltage (the first time of the first low level voltage, the firsthigh level voltage, and the second time of the first low level voltageform a first pulse signal DP1). In some embodiments, when the power loopof the LED tube lamp is conductive, the detection determining circuit3230 detects a first sample signal, such as a voltage signal, on thepower loop. When the first sample signal is greater than or equal to apredefined signal, such as a reference voltage, the installationdetection module determines that the LED tube lamp is correctlyinstalled to the lamp socket according to the application principle ofthis disclosed embodiments described above. Therefore, the detectiondetermining circuit 3230 included in the installation detection moduleoutputs a third high level voltage (also referred to as a first highlevel signal) to the detection result latching circuit 3220 through apath 3231 (also referred to as a second path). The detection resultlatching circuit 3220 receives the third high level voltage (alsoreferred to as the first high level signal) and continues to output asecond high level voltage (also referred to as a second high levelsignal) to the switch circuit 3200. The switch circuit 3200 receives thesecond high level voltage (also referred to as the second high levelsignal) and maintains conducting state to cause the power loop to remainconducting. The detection pulse generating module 3210 does not generateany pulse signal while the power loop remains conductive.

However, in some embodiments, when the first sample signal is smallerthan the predefined signal, the installation detection module, accordingto certain exemplary embodiments as described above, determines that theLED tube lamp has not been correctly installed to the lamp socket.Therefore, the detection determining circuit 3230 outputs a third lowlevel voltage (also referred to as a first low level signal) to thedetection result latching circuit 3220. The detection result latchingcircuit 3220 receives the third low level voltage (also referred to asthe first low level signal) and continues to output a second low levelvoltage (also referred to as a second low level signal) to the switchcircuit 3200. The switch circuit 3200 receives the second low levelvoltage (also referred to as the second low level signal) and then keepsblocking to cause the power loop to remain open. Accordingly, theoccurrence of electric shock caused by touching the conductive part ofthe LED tube lamp which is incorrectly installed in the lamp socket canbe sufficiently avoided.

In some embodiments, when the power loop of the LED tube lamp remainsopen for a period (a period that represents the width (or period) ofpulse signal DP or the pulse-on period of the control signal Sc), thedetection pulse generating module 3210 outputs the first high levelvoltage rising from the first low level voltage to the detection resultlatching circuit 3220 through the path 3211 once more. The detectionresult latching circuit 3220 receives the first high level voltage, andthen simultaneously outputs a second high level voltage to the switchcircuit 3200 and the detection pulse generating module 3210. In someembodiments, when the switch circuit 3200 receives the second high levelvoltage, the switch circuit 3200 conducts again to cause the power loopof the LED tube lamp (in this exemplary embodiment, the power loop atleast includes the first installation detection terminal TE1, the switchcircuit 3200, the path 3201, the detection determining circuit 3230, andthe second installation detection terminal TE2) to be conducting aswell. In the meantime, the detection pulse generating module 3210receives the second high level voltage from the detection resultlatching circuit 3220, and after a period (a period that is utilized todetermine the width (or period) of pulse signal DP), its output from thefirst high level voltage falls back to the first low level voltage (thethird time of the first low level voltage, the second time of the firsthigh level voltage, and the fourth time of the first low level voltageform a second pulse signal DP2). In some embodiments, when the powerloop of the LED tube lamp is conductive again, the detection determiningcircuit 3230 also detects a second sample signal SP2, such as a voltagesignal, on the power loop yet again. When the second sample signal SP2is greater than or equal to the predefined signal (e.g., the referencevoltage Vref), the installation detection module determines, accordingto certain exemplary embodiments described above, that the LED tube lampis correctly installed to the lamp socket. Therefore, the detectiondetermining circuit 3230 outputs a third high level voltage (alsoreferred to as a first high level signal) to the detection resultlatching circuit 3220 through the path 3231. The detection resultlatching circuit 3220 receives the third high level voltage (alsoreferred to as the first high level signal) and continues to output asecond high level voltage (also referred to as a second high levelsignal) to the switch circuit 3200. The switch circuit 3200 receives thesecond high level voltage (also referred to as the second high levelsignal) and maintains a conducting state to cause the power loop toremain conducting. The detection pulse generating module 3210 does notgenerate any pulse signal while the power loop remains conductive.

In some embodiments, when the second sample signal SP2 is smaller thanthe predefined signal, the installation detection module determines,according to certain exemplary embodiments described above, that the LEDtube lamp has not been correctly installed to the lamp socket.Therefore, the detection determining circuit 3230 outputs the third lowlevel voltage (also referred to as the first low level signal) to thedetection result latching circuit 3220. The detection result latchingcircuit 3220 receives the third low level voltage (also referred to asthe first low level signal) and continues to output the second low levelvoltage (also referred to as the second low level signal) to the switchcircuit 3200. The switch circuit 3200 receives the second low levelvoltage (also referred to as the second low level signal) and then keepsblocking to cause the power loop to remain open. According to thedisclosure mentioned above, the pulse width (i.e., pulse on-time) andthe pulse period are dominated by the pulse signal provided by thedetection pulse generating module 3210 during the detection mode DTM;and the signal level of the control signal is determined according tothe detection result signal Sdr provided by the detection determiningcircuit 3230 after the detection mode DTM.

According to the embodiments of FIG. 41B, since the signal level of thefirst sample signal SP1 generated based on the first pulse signal DP1and the second sample signal SP2 generated based on the second pulsesignal DP2 are smaller than the reference voltage Vref, the switchcircuit 3200 is maintained to be cut off and the driving circuit (notshown) does not perform effective power conversion during the timepointts to td (i.e., the detection mode DTM). The effective power conversionrefers to generating sufficient power for driving the LED module to emitlight. The detection determining circuit 3230 generates a detectionresult, indicating the LED tube lamp has been correctly installed or isnot touched by a user, according to the third sample signal SP3 greaterthan the reference voltage Vref during the pulse-on period of the thirdpulse signal DP3, so that the switch circuit 3200 is maintained in theconducting state in response to the high level voltage output by thedetection result latching circuit 3220 and the power loop is thereforemaintained in the conducting state as well. After the power loop isconducting, the driving circuit of the power supply module starts tooperate based on the voltage on the power loop, so as to generate thelighting control signal Slc for controlling the conducting state of thepower switch (not shown).

Next, referring to FIG. 16B to FIG. 16E at the same time, in someembodiments when an LED tube lamp is being installed to a lamp socket,the capacitor C21 is charged by the driving signal VCC, for example,Vcc, through the resistor R21. And when the voltage of the capacitor C21rises enough to trigger the Schmitt trigger STRG, the Schmitt triggerSTRG outputs a first high level voltage rising from a first low levelvoltage in an initial state to an input end of the OR gate OG. After theOR gate OG receives the first high level voltage from the Schmitttrigger STRG, the OR gate OG outputs a second high level voltage to thebase of the transistor M22 and the resistor R23. When the base of thetransistor M22 receives the second high level voltage from the OR gateOG, the collector and the emitter of the transistor M22 are conductingto further cause the power loop of the LED tube lamp (in this exemplaryembodiment, the power loop at least includes the first installationdetection terminal TE1, the transistor M22, the resistor STRG, and thesecond installation detection terminal TE2) to be conducting as well. Inthe meantime, the base of the transistor M21 receives the second highlevel voltage from the OR gate OG through the resistor R23, and then thecollector and the emitter of the transistor M21 are conductive andgrounded to cause the voltage of the capacitor C21 to be discharged tothe ground through the resistor R22. In some embodiments, when thevoltage of the capacitor C21 is not enough to trigger the Schmitttrigger STRG, the Schmitt trigger STRG outputs the first low levelvoltage falling from the first high level voltage (a first instance of afirst low level voltage at a first time, followed by a first high levelvoltage, followed by a second instance of the first low level voltage ata second time form a first pulse signal DP1). When the power loop of theLED tube lamp is conductive, the current passing through the capacitorin the power loop, such as, the capacitor of the filtering circuit, bytransient response flows through the transistor M22 and the resistor R24and forms a voltage signal on the resistor R24. The voltage signal iscompared to a reference voltage, for example, 1.3V, but the referencevoltage is not limited thereto, by the comparator CP21. When the voltagesignal is greater than and/or equal to the reference voltage, thecomparator CP21 outputs a third high level voltage to the clock inputend CLK of the D flip-flop DFF. In the meantime, since the data inputend D of the D flip-flop DFF is connected to the driving signal VCC, theD flip-flop DFF outputs a high level voltage (at its output end Q) toanother input end of the OR gate OG. This causes the OR gate OG to keepoutputting the second high level voltage to the base of the transistorM22, and further results in the transistor M22 and the power loop of theLED tube lamp remaining in a conducting state. Besides, since the ORgate OG keeps outputting the second high level voltage to cause thetransistor M21 to be conducting to the ground, the capacitor C21 isunable to reach an enough voltage to trigger the Schmitt trigger STRG.

However, when the voltage signal on the resistor R24 is smaller than thereference voltage, the comparator CP21 outputs a third low level voltageto the clock input end CLK of the D flip-flop DFF. In the meantime,since the initial output of the D flip-flop DFF is a low level voltage(e.g., zero voltage), the D flip-flop DFF outputs a low level voltage(at its output end Q) to the other input end of the OR gate OG.Moreover, the Schmitt trigger STRG connected by the input end of the ORgate OG also restores outputting the first low level voltage, the ORgate OG thus keeps outputting the second low level voltage to the baseof the transistor M22, and further results in the transistor M22 toremain in a blocking state (or an off state) and the power loop of theLED tube lamp to remain in an open state. Still, since the OR gate OGkeeps outputting the second low level voltage to cause the transistor2764 to remain in a blocking state (or an off state), the capacitor C21is charged by the driving voltage VCC through the resistor R21 onceagain for next (pulse signal) detection.

In some embodiments, the cycle (or interval TIV) of the pulse signal isdetermined by the values of the resistor R21 and the capacitor C21. Incertain cases, the cycle of the pulse signal may include a value rangingfrom about 3 milliseconds to about 500 milliseconds or may be rangingfrom about 20 milliseconds to about 50 milliseconds. In some cases, thecycle of the pulse signal may include a value ranging from about 500milliseconds to about 2000 milliseconds. In some embodiments, the width(or period) of the pulse signal is determined by the values of theresistor R22 and the capacitor C21. In certain cases, the width of thepulse signal may include a value ranging from about 1 microsecond toabout 100 microseconds or may be ranging from about 10 microseconds toabout 20 microseconds. In the embodiments of FIG. 16B and FIG. 16C,descriptions of mechanisms for generating pulse signal(s) and ofcorresponding states of applied detection current are according tocertain embodiments can be seen referring to those of the embodiments ofFIG. 41D-41F, and thus are not presented here again.

The Zener diode ZD1 provides a protection function but it may be omittedin certain cases. The resistor STRG may include two resistors connectedin parallel based on the consideration of power consumption in certaincases, and its equivalent resistance may include a value ranging fromabout 0.1 ohm to about 5 ohm. The resistors R25 and R26 provides thefunction of voltage division to make the input of the comparator CP22bigger than the reference voltage, such as 0.3V, but the value of thereference voltage is not limited thereto. The capacitor C22 provides thefunctions of regulation and filtering. The diode D21 limits the signalto be transmitted in one way. In addition, the installation detectionmodule disclosed by the example embodiments may also be adapted to othertypes of LED lighting equipment with dual-end power supply, e.g., theLED lamp directly using commercial power as its external driving signal.However, the invention is not limited to the above example embodiments.

Based on the embodiments illustrated in FIG. 16A to FIG. 16E, comparedto the installation detection module of FIG. 15A, the installationdetection module illustrated in FIG. 16A uses the control signal outputby the detection result latching circuit 3220 for the reference ofdetermining the end of the pulse or resetting the pulse signal byfeeding back the control signal to the detection pulse generating module3210. Since the pulse on-time is not merely determined by the detectionpulse generating module 3210, the circuit design of the detection pulsegenerating module can be simplified. Compared to the detection pulsegenerating module illustrated in FIG. 15B, the number of the componentsof the detection pulse generating module illustrated in FIG. 16B is lessthan the detection pulse generating module 3110, and thus the detectionpulse generating module 3210 may have lower power consumption and may bemore suitable for integrated design.

Referring to FIG. 17A, a block diagram of an installation detectionmodule according to an exemplary embodiment is illustrated. Theinstallation detection module 3000 c includes a pulse generatingauxiliary circuit 3310, an integrated control module 3320, a switchcircuit 3200 c, and a detection determining auxiliary circuit 3330. Theoperation of the installation detection module of the present embodimentis similar to the embodiment of FIGS. 16A to 16C, and thus the signalwaveform of the present embodiment can refer to the embodimentillustrated in FIG. 41B. The integrated control module 3320 includes atleast three pins such as two input terminals IN1 and IN2 and an outputterminal OT. The pulse generating auxiliary circuit 3310 is connected tothe input terminal IN1 and the output terminal OT of the integratedcontrol module 3320 and configured to assist the integrated controlmodule 3320 for generating a control signal. The detection determiningauxiliary circuit 3330 is connected to the input terminal IN2 of theintegrated control module 3320 and the switch circuit 3200 c andconfigured to transmit a sample signal related to the signal passingthrough the LED power loop to the input terminal IN2 of the integratedcontrol module 3320 when the switch circuit 3200 c and the LED powerloop are conducting, such that the integrated control module 3320 maydetermine an installation state between the LED tube lamp and the lampsocket according to the sample signal. For example, the sample signalmay be based on an electrical signal passing through the power loopduring the pulse-on period of the pulse signal (e.g., the rising portionof the pulse signal). Switch circuit 3200 c is connected between one endof the LED power loop and the detection determining auxiliary circuit3330 and configured to receive the control signal, outputted by theintegrated control module 3320, in which the LED power loop isconducting during an enable period of the control signal (i.e., thepulse-on period).

Specifically, under the detection mode DTM, the integrated controlmodule 3320 temporarily causes the switch circuit 3200 c to conduct,according to the signal received from the input terminal IN1, byoutputting the control signal having at least one pulse. During thedetection mode DTM, the integrated control module 3320 may detectwhether the LED tube lamp is properly connected to the lamp socket andlatch the detection result according to the signal on the input terminalIN2. The detection result is regarded as the basis of whether to causethe switch circuit 3200 c to conduct after the detection mode DTM (i.e.,it determines whether to provide power to LED module). The detailcircuit structure and operations of the present embodiment will bedescribed below.

Referring to FIG. 17B, an inner circuit diagram of an integrated controlmodule according to some exemplary embodiments is illustrated. Theintegrated control module 3320 includes a pulse generating unit 3322, adetection result latching unit 3323, and a detection unit 3324. Thepulse generating unit 3322 receives the signal provided by the pulsegenerating auxiliary circuit 3310 from the input terminal IN1 andaccordingly generates a pulse signal. The generated pulse signal will beprovided to the detection result latching unit 3323. In an exemplaryembodiment, the pulse generating unit 3322 can be implemented by aSchmitt trigger (not shown, it can use a Schmitt trigger such as STRGillustrated in FIG. 16B). According to the exemplary embodimentmentioned above, the Schmitt trigger has an input end coupled to theinput terminal IN1 of the integrated control module 3320 and an outputterminal coupled to the output terminal OT of the integrated controlmodule 3320 (e.g., through the detection result latching unit 3323). Itshould be noted that, the pulse generating unit 3322 is not limited tobe implemented by the Schmitt trigger, any analog/digital circuitcapable of implementing the function of generating the pulse signalhaving at least one pulse may be utilized in some disclosed embodiments.

The detection result latching unit 3323 is connected to the pulsegenerating unit 3322 and the detection unit 3324. During the detectionmode DTM, the detection result latching unit 3323 outputs the pulsesignal generated by the pulse generating unit 3322 as the control signalto the output terminal OT. On the other hand, the detection resultlatching unit 3323 further stores the detection result signal Sdrprovided by the detection unit 3324 and outputs the stored detectionresult signal Sdr to the output terminal OT after the detection modeDTM, so as to determine whether to cause the switch circuit 3200 c toconduct according to the installation state of the LED tube lamp. In anexemplary embodiment, the detection latching unit 3323 can beimplemented by a circuit structure constituted by a D flip-flop and anOR gate (not shown, for example it can use the D flip-flop DFF and ORgate OG illustrated in FIG. 16D). According to the exemplary embodimentmentioned above, the D flip-flop has a data input end connected to thedriving voltage VCC, a clock input end connected to the detection unit3324, and an output end. The OR gate has a first input end connected tothe pulse generating unit 3322, a second input end connected to theoutput end of the D flip-flop, and an output end connected to the outputterminal OT. It should be noted that, the detection result latching unit3323 is not limited to be implemented by the aforementioned circuitstructure, any analog/digital circuit capable of implementing thefunction of latching and outputting the control signal to control theswitching of the switch circuit may be utilized in the presentinvention.

The detection unit 3324 is coupled to the detection result latching unit3323. The detection unit 3324 receives the signal provided by thedetection determining auxiliary circuit 3330 from the input terminal IN2and accordingly generates the detection result signal Sdr indicating theinstallation state of the LED tube lamp, in which the generateddetection result signal Sdr will be provided to the detection resultlatching unit 3323. In an exemplary embodiment, detection unit 3324 canbe implemented by a comparator (not shown, it can be, for example, thecomparator CP21 illustrated in FIG. 16C). According to the exemplaryembodiment mentioned above, the comparator has a first input endreceiving a setting signal, a second input end connected to the inputterminal IN2, and an output end connected to the detection resultlatching unit 3323. It should be noted that, the detection unit 3324 isnot limited to be implemented by the comparator, any analog/digitalcircuit capable of implementing the function of determining theinstallation state based on the signal on the input terminal IN2 may beutilized in some disclosed embodiments.

Referring to FIG. 17C, a circuit diagram of a pulse generating auxiliarycircuit according to some exemplary embodiments is illustrated. Thepulse generating auxiliary circuit 3310 includes resistors R31, R32, andR33, a capacitor C31, and a transistor M31. The resistor R31 has an endconnected to a driving voltage (e.g., VCC). The capacitor C31 has an endconnected to another end of the resistor R31, and another end connectedto ground. The resistor R32 has an end connected to the connection nodeof the resistor R31 and the capacitor C31. The transistor M31 has abase, a collector connected to another end of the resistor R32, and anemitter connected to the ground. The resistor R33 has an end connectedto the base of the transistor M31, and another end connected to theoutput terminal OT of the integrated control module 3320 and the controlterminal of the switch circuit 3200 c via the path 3311. The pulsegenerating auxiliary circuit 3310 further includes a Zener diode ZD1.The Zener diode ZD1 has an anode connected to another end of thecapacitor C31 and the ground and a cathode connected to the endconnecting the capacitor C31 and the resistor R31.

Referring to FIG. 17D, a circuit diagram of a detection determiningauxiliary circuit according to some exemplary embodiments isillustrated. The detection determining auxiliary circuit 3330 includesresistors R34, R35 and R36, a capacitor C32 and diode D31. The resistorR34 has an end connected to the switch circuit 3200 c, and another endconnected to another end of the LED power loop (e.g., the secondinstallation detection terminal TE2). The resistor R35 has an endconnected to the driving voltage (e.g., VCC). The resistor R36 has anend connected to another end of the resistor R35 and the input terminalIN2 of the integrated control module 3320 via the path 3331, and anotherend connected to the ground. The capacitor C32 is connected to theresistor R36 in parallel. The diode D31 has an anode connected to theend of the resistor R34 and a cathode connected to the connection nodeof the resistors R35 and R36. In one exemplary embodiment, the resistorsR35 and R36, the capacitor C32, and the diode D31 can be omitted. Whenthe diode D31 is omitted, one end of the resistor R34 is directlyconnected to the input terminal IN2 of the integrated control module3320 via the path 3331. In another one exemplary embodiment, theresistor R34 can be implemented by two paralleled resistors based on thepower consideration, in which the equivalent resistance of eachresistors can be 0.1 ohm to 5 ohm.

Referring to FIG. 17E, a circuit diagram of a switch circuit accordingto some exemplary embodiments is illustrated. The switch circuit 3200 cincludes a transistor M32. The transistor M32 has a base connected tothe output terminal OT of the integrated control module 3320 via thepath 3321, a collector connected to one end of the LED power loop (e.g.,the first installation detection terminal TE1), and an emitter connectedto the detection determining auxiliary circuit. In some embodiments, thetransistor M32 may be replaced by other equivalently electronic parts,e.g., a MOSFET.

It should be noted that, the installation detection module of thepresent embodiment utilizes the same installation detection principle asthe aforementioned embodiment. For example, the capacitor voltage maynot mutate; the voltage of the capacitor in the power loop of the LEDtube lamp before the power loop being conductive is zero and thecapacitor's transient response may appear to have a short-circuitcondition; when the LED tube lamp is correctly installed to the lampsocket, the power loop of the LED tube lamp in transient response mayhave a smaller current-limiting resistance and a bigger peak current;and when the LED tube lamp is incorrectly installed to the lamp socket,the power loop of the LED tube lamp in transient response may have abigger current-limiting resistance and a smaller peak current. Thisembodiment may also meet the UL standard to make the leakage current ofthe LED tube lamp less than 5 MIU. For example, the present embodimentmay determine whether the LED tube lamp is correctly/properly connectedto the lamp socket by detecting the transient response of the peakcurrent. Therefore, the detail operation of the transient current underthe correct installation state and the incorrect installation state maybe seen by referring to the aforementioned embodiment, and it will notbe repeated herein. The following disclosure will focus on describingthe entire circuit operation of the installation detection moduleillustrated in FIG. 17A to 17E.

Referring to FIG. 17A again, when an LED tube lamp is being installed toa lamp socket, the driving voltage may be provided to modules/circuitswithin the installation detection module 3000 c when power is providedto at least one end cap of the LED tube lamp. The pulse generatingauxiliary circuit 3310 starts charging in response to the drivingvoltage. The output voltage (referred to “first output voltage”hereinafter) of the pulse generating auxiliary circuit 3310 rises from afirst low level voltage to a voltage level greater than a forwardthreshold voltage after a period (e.g., the period utilized to determinethe cycle of a pulse signal), in which the first output voltage mayoutput to the input terminal of the integrated control module 3320 viathe path 3311. After receiving the first output voltage from the inputterminal IN1, the integrated control module 3320 outputs an enabledcontrol signal (e.g., a high level voltage) to the switch circuit 3200 cand the pulse generating auxiliary circuit 3310. When the switch circuit3200 c receives the enabled control signal, the switch circuit 3200 c isturned on so that a power loop of the LED tube lamp is conducted aswell. Herein, at least the first installation detection terminal TE1,the switch circuit 3200 c, the path 3201, the detection determiningauxiliary circuit 3330 and the second installation detection terminalTE2 are included in the power loop. In the meantime, the pulsegenerating auxiliary circuit 3310 conducts a discharge path fordischarging in response to the enabled control signal. The first outputvoltage falls down to the first low level voltage from the voltagegreater than the forward threshold voltage. When the first outputvoltage is less than a reverse threshold voltage (which can be definedbased on the circuit design), the integrated control module 3320 pullsthe enabled control signal down to a disable level in response to thefirst output voltage (i.e., the integrated control module 3320 outputs adisabled control signal, in which the disabled control signal is, forexample, a low level voltage), and thus the control signal has apulse-type signal waveform (i.e., the first time of the first low levelvoltage, the first high level voltage, and the second time of the firstlow level voltage form a first pulse signal DP1). When the power loop isconducting, the detection determining auxiliary circuit 3330 detects afirst sample signal (e.g., voltage signal) on the power loop andprovides the first sample signal to the integrated control module 3320via the input terminal IN2. When the integrated control module 3320determines the first sample signal is greater than or equal to a settingsignal (e.g., a reference voltage), which may represent the LED tubelamp has been properly installed in the lamp socket, the integratedcontrol module 3320 outputs and keeps the enabled control signal to theswitch circuit 3200 c. Since receiving the enabled control signal, theswitch circuit 3200 c remains in the conductive state so that the powerloop of the LED tube lamp is kept on the conductive state as well.During the period when the switch circuit 3200 c receives the enabledcontrol signal, the integrated control module 3320 does not output thepulses anymore.

On the contrary, when the integrated control module 3320 determines thefirst sample signal is less than the setting signal, which may representthe LED tube lamp has not been properly installed in the lamp socketyet, the integrated control module 3320 outputs and keeps the disabledcontrol signal to the switch circuit 3200 c. As a result of receivingthe disabled control signal, the switch circuit 3200 c remains in thenon-conducting state so that the power loop of the LED tube lamp is kepton the non-conducting state as well.

Since the discharge path of the pulse generating auxiliary circuit 3310is cut off, the pulse generating auxiliary circuit 3310 starts to chargeagain. Therefore, after the power loop of the LED tube lamp remains in anon-conducting state for a period (i.e., pulse on-time), the firstoutput voltage of the pulse generating auxiliary circuit 3310 rises fromthe first low level voltage to the voltage greater than the forwardthreshold voltage again, in which the first output voltage may output tothe input terminal of the integrated control module 3320 via the path3311. After receiving the first output voltage from the input terminalIN1, the integrated control module 3320 pulls up the control signal fromthe disable level to an enable level (i.e., the integrated controlmodule 3320 outputs the enabled control signal) and provides the enabledcontrol signal to the switch circuit 3200 c and the pulse generatingauxiliary circuit 3310. When the switch circuit 3200 c receives theenabled control signal, the switch circuit 3200 c is turned on so thatthe power loop of the LED tube lamp is conducted as well. Herein, atleast the first installation detection terminal TE1, the switch circuit3200 c, the path 3201, the detection determining auxiliary circuit 3330and the second installation detection terminal TE2 are included in thepower loop. In the meantime, the pulse generating auxiliary circuit 3310conducts, in response to the enabled control signal, a discharge pathagain for discharging. The first output voltage gradually falls down tothe first low level voltage from the voltage greater than the forwardthreshold voltage again. When the first output voltage is less than areverse threshold voltage (which can be defined based on the circuitdesign), the integrated control module 3320 pulls the enabled controlsignal down to a disable level in response to the first output voltage(i.e., the integrated control module 3320 outputs a disabled controlsignal, in which the disabled control signal is, for example, a lowlevel voltage), and thus the control signal has a pulse-type signalwaveform (i.e., the third time of the first low level voltage, thesecond time of the high level voltage, and the fourth time of the firstlow level voltage form a second pulse signal DP2). When the power loopis conducted again, the detection determining auxiliary circuit 3330detects a second sample signal (e.g., voltage signal) on the power loopand provides the second sample signal to the integrated control module3320 via the input terminal IN2. When the integrated control module 3320determines the second sample signal is greater than or equal to asetting signal (e.g., a reference voltage), which may represent the LEDtube lamp has been properly installed in the lamp socket, the integratedcontrol module 3320 outputs and keeps the enabled control signal to theswitch circuit 3200 c. Since receiving the enabled control signal, theswitch circuit 3200 c remains in the conductive state so that the powerloop of the LED tube lamp is kept on the conductive state as well.During the period when the switch circuit 3200 c receives the enabledcontrol signal, the integrated control module 3320 does not output thepulses anymore.

When the integrated control module 3320 determines the second samplesignal is less than the setting signal, which may represent the LED tubelamp has not been properly installed in the lamp socket yet, theintegrated control module 3320 outputs and keeps the disabled controlsignal to the switch circuit 3200 c. Since receiving the disabledcontrol signal, the switch circuit 3200 c remains in the non-conductingstate so that the power loop of the LED tube lamp is kept on thenon-conducting state as well. Based on the above operation, when the LEDtube lamp has not been properly installed in the lamp socket, theproblem in which users may get electric shock caused by touching theconductive part of the LED tube lamp can be prevented.

Operation of circuits/modules within the installation detection moduleis further described below. Referring to FIG. 17B to 17E, when the LEDtube lamp is installed in the lamp socket, the capacitor C31 is chargedby a driving voltage VCC via resistor R31. When the voltage of thecapacitor C31 is raised to trigger the pulse generating unit 3322 (i.e.,the voltage of the capacitor C31 is raised greater than the forwardthreshold voltage), the output of the pulse generating unit 3322 changesto a first high level voltage from an initial first low level voltageand provides to the detection result latching unit 3323. After receivingthe first high level voltage outputted by the pulse generating unit3322, the detection result latching unit 3323 outputs a second highlevel voltage to the base of the transistor M32 and the resistor R33 viathe output terminal OT. After the second high level voltage outputtedfrom the detection result latching unit 3323 is received by the base ofthe transistor M32, the collector and the emitter of the transistor areconducted so as to conduct the power loop of the LED tube lamp. Herein,at least the first installation detection terminal TE1, the transistorM32, the resistor R34, and the second installation detection terminalTE2 are included in the power loop.

In the meantime, the base of the transistor M31 receives the second highlevel voltage on the output terminal OT via the resistor R33. Thecollector and the emitter of the transistor M31 are conducting andconnected to the ground, such that the capacitor C31 discharges to theground via the resistor R32. When the voltage of the capacitor C31 isinsufficient so that the pulse generating unit 3322 cannot be triggered,the output of the pulse generating unit 3322 is pulled down to the firstlow level voltage from the first high level voltage (i.e., the firsttime of the first low level voltage, the first high level voltage, andthe second time of the first low level voltage form a first pulse signalDP1). When the power loop is conducting, the current, generated by thetransient response, passing through a capacitor (e.g., filteringcapacitor in the filtering circuit) in the LED power loop flows throughthe transistor M32 and the resistor R34 so as to build a voltage signalon the resistor R34. The voltage signal is provided to the inputterminal IN2, and thus the detection unit 3324 may compare the voltagesignal on the input terminal IN2 (i.e., the voltage on the resistor R34)with a reference voltage.

When the detection unit 3324 determines the voltage signal on theresistor R34 is greater than or equal to the reference voltage, thedetection unit outputs a third high level voltage to the detectionresult latching unit 3323. On the contrary, when the detection unit 3324determines the voltage signal on the resistor R34 is less than thereference voltage, the detection unit 3324 outputs a third low levelvoltage to the detection result latching unit 3323.

The detection result latching unit 3323 latches/stores the third highlevel voltage/third low level voltage provided by the detection unit3324 and performs a logic operation based on the latched/stored signaland the signal provided by the pulse generating unit 3322, such that thedetection result latching unit 3323 outputs the control signal. Herein,the result of the logic operation determines whether the signal level ofthe outputted control signal is the second high level voltage or thesecond low level voltage.

More specifically, when the detection unit 3324 determines that thevoltage signal on the resistor is greater than or equal to the referencevoltage, the detection result latching unit 3323 may latch the thirdhigh level voltage outputted by the detection unit 3324, and the secondhigh level voltage is maintained to be output to the base of thetransistor M32, so that the transistor M32 and the power loop of the LEDtube lamp maintain the conductive state. Since the detection resultlatching unit 3323 may continuously output the second high levelvoltage, the transistor M31 is conducted to the ground as well, so thatthe voltage of the capacitor C31 cannot rise enough to trigger the pulsegenerating unit 3322. When the detection unit 3324 determines that thevoltage signal on the resistor R34 is less than the reference voltage,both the detection unit 3324 and the pulse generating unit 3322 providea low level voltage, and thus the detection result latching unit 3323continuously outputs, after performing the OR logical operation, thesecond low level voltage to the base of the transistor M32. Therefore,the transistor M32 is maintained to be cut off and the power loop of theLED tube lamp is maintained in the non-conducting state. However, sincethe control signal on the output terminal OT is maintained at a secondlow level voltage, the transistor M31 is thus maintained in a cut-offstate as well, and repeatedly performs the next (pulse) detection untilthe capacitor C31 is charged by the driving voltage VCC via the resistorR31 again.

It should be noted that, the detection mode DTM described in thisembodiment can be defined as the period that the driving voltage VCC isprovided to the installation detection module 3000 c, however, thedetection unit 3324 has not yet determined that the voltage signal onthe resistor R34 is greater than or equal to the reference voltage.During the detection mode DTM, since the control signal outputted by thedetection result latching unit 3323 alternatively conducts and cuts offthe transistor M31, the discharge path is periodically conducted and cutoff, correspondingly. Thus, the capacitor C31 is periodically chargedand discharged in response to the conducting state of the transistorM31, so that the detection result latching unit 3323 outputs the controlsignal having a periodic pulse waveform during the detection mode DTM.The detection mode DTM ends when the detection unit 3324 determines thatthe voltage signal on the resistor R34 is greater than or equal to thereference voltage or the driving voltage VCC is stopped. The detectionresult latching unit 3323 is maintained to output the control signalhaving the second high level voltage or the second low level voltageafter the detection mode DTM.

In one embodiment, compared to the exemplary embodiment illustrated inFIG. 16A, the integrated control module 3320 is constituted byintegrating part of the circuit components in the detection pulsegenerating module 3210, the detection result latching circuit 3220, andthe detection determining circuit 3230 (e.g., as part of an integratedcircuit). Another part of the circuit components which are notintegrated in the integrated control module 3320 constitutes the pulsegenerating auxiliary circuit 3310 and the detection determiningauxiliary circuit 3330 of the embodiment illustrated in FIG. 17A. Insome embodiments, the function/circuit configuration of the combinationof the pulse generating unit 3322 in the integrated control module 3320and the pulse generating auxiliary circuit 3310 can be equivalent to thedetection pulse generating module 3210. The function/circuitconfiguration of the detection result latching unit 3323 in theintegrated control module 3320 can be equivalent to the detection resultlatching module 3220. The function/circuit configuration of thecombination of the detection unit 3324 in the integrated control module3320 and the detection determining auxiliary circuit 3330 can beequivalent to the detection determining circuit 3230. In theseembodiments, the circuit elements included in the pulse generating unit3322, the detection result latching unit 3323, and the detection unit3324 are included in an integrated circuit (e.g., formed on a die orchip).

Referring to FIG. 18A, an internal circuit block diagram of athree-terminal switch device according to an exemplary embodiment isillustrated. The installation detection module according to oneembodiment is, for example, a three-terminal switch device 3000 dincluding a power terminal VP1, a first switching terminal SP1, and asecond switching terminal SP2. The power terminal VP1 of thethree-terminal switch device 3000 d is adapted to receive a drivingvoltage VCC. The first switching terminal SP1 is adapted to connect oneof the first installation detection terminal TE1 and the secondinstallation detection terminal TE2 (the first switching terminal SP1 isillustrated as being connected to the first installation detectionterminal TE1 in FIG. 18A, but the invention is not limited thereto), andthe second switching terminal SP2 is adapted to connect to the other oneof the first installation detection terminal TE1 and the secondinstallation detection terminal TE2 (the second switching terminal SP2is illustrated as being connected to the second installation detectionterminal TE2 in FIG. 18A, but the invention is not limited thereto).

The three-terminal switch device 3000 d includes a signal processingunit 3420, a signal generating unit 3410, a signal capturing unit 3430,and a switch unit 3200 d. In addition, the three-terminal switch device3000 d further includes an internal power detection unit 3440. Thesignal processing unit 3420 outputs a control signal having a pulse ormulti-pulse waveform during a detection mode DTM, according to thesignal provided by the signal generating unit 3410 and the signalcapturing unit 3430. The signal processing unit 3420 outputs the controlsignal, in which the signal level of the control signal remains at ahigh level voltage or a low voltage level, after the detection mode DTM,so as to control the conducting state of the switch unit 3200 d anddetermine whether to conduct the power loop of the LED tube lamp. Thepulse signal generated by the signal generating unit 3410 can begenerated according to a reference signal received from outside, or byitself, and the present invention is not limited thereto. The term“outside” described in this paragraph is relative to the signalgenerating unit 3410, which means the reference signal is not generatedby the signal generating unit 3410. As such, whether the referencesignal is generated by any of the other circuits within thethree-terminal switch device 3000 d, or by an external circuit of thethree-terminal switch device 3000 d, those embodiments belong the scopeof “the reference signal received from the outside” as described in thisparagraph. The signal capturing unit 3430 samples an electrical signalpassing through the power loop of the LED tube lamp to generate a samplesignal and detects an installation state of the LED tube lamp accordingto the sample signal, so as to transmit a detection result signal Sdrindicating the detection result to the signal processing unit 3420 forprocessing.

In an exemplary embodiment, the three-terminal switch device 3000 d canbe implemented by an integrated circuit. For example, the three-terminalswitch device 3000 d can be a three-terminal switch control chip, whichcan be utilized in any type of the LED tube lamp having two end caps forreceiving power so as to provide the function of preventing electricshock. It should be noted that, the three-terminal switch device 3000 dis not limited to merely include three pins/connection terminals. Forexample, a multi-pins switch device (with more than three pins) havingat least three pins having the same configuration and function as theembodiment illustrated in FIG. 18A can include additional pins for otherpurposes, even though those pins may be not described in detail herein.It should be noted that the various “units” described herein, in someembodiments, are circuits, and will be described as circuits.

In an exemplary embodiment, the signal processing unit 3420, the signalgenerating unit 3410, the signal capturing unit 3430, the switch unit3200 d, and the internal power detection unit 3440 can be respectivelyimplemented the circuit configurations illustrated in FIG. 18B to 18F,but the present invention is not limited thereto. Detail exemplaryoperation of each of the units in the three-terminal control chip aredescribed below.

Referring to FIG. 18B, a block diagram of a signal processing unitaccording to an exemplary embodiment is illustrated. The signalprocessing unit 3420, which in one embodiment is a circuit, includes adriver DRV, an OR gate OG, and a D flip-flop DFF. The driver DRV has aninput end, and has an output end connected to the switch unit 3200 d viathe path 3421, in which the driver DRV provides the control signal tothe switch unit 3200 d via the output end and the path 3421. The OR gateOG has a first input end connected to the signal generating unit 3410via the path 3411, a second input end, and an output end connected tothe input end of the driver DRV. The D flip-flop DFF has a data inputend (D) receiving a driving voltage VCC, a clock input end (CK)connected to the signal capturing unit 3430 via the path 3431, and anoutput connected to the second input terminal of the OR gate OG.

Referring to FIG. 18C, a block diagram of a signal generating unitaccording to an exemplary embodiment is illustrated. The signalgenerating unit 3410 includes resistors R41 and R42, a capacitor C41, aswitch M41, and a comparator CP41. One end of the resistor R41 receivesthe driving voltage VCC, and the resistors R41 and R42 and the capacitorC41 are serial connected between the driving voltage VCC and the ground.The switch M41 is connected to the capacitor C41 in parallel. Thecomparator CP41 has a first input end connected to the connection nodeof the resistors R41 and R42, a second input end receives a referencevoltage Vref, and an output end connected to the control terminal of theswitch M41.

Referring to FIG. 18D, a block diagram of a signal capturing unitaccording to an exemplary embodiment is illustrated. The signalcapturing unit 3430 includes an OR gate and comparators CP42 and CP43.The OR gate OG has a first input end and a second input end, and anoutput end connected to the signal processing unit 3420 via the path3431. The comparator CP42 has a first input end connected to one end ofthe switch unit 3200 d (i.e., a node on the power loop of the LED tubelamp) via the path 3202, a second input end receiving a first referencevoltage (e.g., 1.25V, but not limited thereto), and an output endconnected to the first input end of the OR gate OG. The comparator CP43has a first input end connected to a second reference voltage (e.g.,0.15V, but not limited thereto), a second input end connected to thefirst input end of the comparator CP42, and an output end connected tothe second input end of the OR gate OG.

Referring to FIG. 18E, a block diagram of a switch unit according to anexemplary embodiment is illustrated. The switch unit 3200 d includes atransistor M42. The transistor M42 has a gate connected to the signalprocessing unit 3420 via the path 3421, a drain connected to the firstswitch terminal SP1 via the path 3201, and a source connected to thesecond switch terminal SP2, the first input end of the comparator CP42,and the second input end of the comparator CP43 via the path 3202. Inone embodiment, for example, the transistor M42 is an NMOS transistor.

Referring to FIG. 18F, a block diagram of an internal power detectionunit according to an exemplary embodiment is illustrated. The internalpower detection unit 3440 includes a clamp circuit 3442, a referencevoltage generating circuit 3443, a voltage adjustment circuit 3444, anda Schmitt trigger STRG. The clamp circuit 3442 and the voltageadjustment circuit 3444 are respectively connected to the power terminalVP1 for receiving the driving voltage, so as to perform a voltage clampoperation and a voltage level adjustment operation, respectively. Thereference voltage generating circuit 3443 is coupled to the voltageadjustment circuit 3444 and is configured to generate a referencevoltage to the voltage adjustment circuit 3444. The Schmitt trigger STRGhas an input end coupled to the clamp circuit 3442 and the voltageadjustment circuit 3444, and an output end to output a powerconfirmation signal for indicating whether the driving voltage VCC isnormally supplied. If the driving voltage VCC is normally supplied, theSchmitt trigger STRG outputs the enabled power confirmation signal, suchthat the driving voltage VCC is allowed to be provided to thecomponent/circuit within the three-terminal switch device 3000 d. On thecontrary, if the driving voltage VCC is abnormal, the Schmitt triggerSTRG outputs the disabled power confirmation signal, such that thecomponent/circuit within the three-terminal switch device 3000 d won'tbe damaged based on working under the abnormal driving voltage VCC.

Referring to FIG. 18A to 18F, under the circuit operation of the presentembodiment, when the LED tube lamp is installed in the lamp socket, thedriving voltage VCC is provided to the three-terminal switch device 3000d via the power terminal VP1. At this time, the driving voltage VCCcharges the capacitor C41 via the resistors R41 and R42. When thecapacitor voltage is raised greater than the reference voltage Vref, thecomparator CP41 switches to output a high level voltage to the firstinput end of the OR gate OG and the control terminal of the switch M41.The switch M41 is conducted in response to the received high levelvoltage, such that the capacitor starts to discharge to the ground. Thecomparator CP41 outputs an output signal having pulse-type waveformthrough this charge and discharge process.

During the period when the comparator CP41 outputs the high levelvoltage, the OR gate OG correspondingly outputs the high level voltageto conduct the transistor M42, such that the current flows through thepower loop of the LED tube lamp. When the current passes the power loop,a voltage signal corresponding to the current size can be established onthe path 3202. The comparator CP42 samples the voltage signal andcompares the signal level of the voltage signal with the first referencevoltage (e.g., 1.25V).

When the signal level of the sampled voltage signal is greater than thefirst reference voltage, the comparator CP42 outputs the high levelvoltage. The OR gate OG generates another high level voltage to theclock input end of the D flip-flop DFF in response to the high levelvoltage outputted by the comparator CP42. The D flip-flop DFFcontinuously outputs the high level voltage based on the output of theOR gate OG. Driver DRV generates an enabled control signal to conductthe transistor M42 in response to the high level voltage on the inputterminal. At this time, even if the capacitor C41 has been discharged tobelow the reference voltage Vref and thus the output of the comparatorCP41 is pulled down to the low level voltage, the transistor M42 stillremains in the conductive state since the output of the D flip-flop DFFis kept on the high level voltage.

When the sampled voltage signal is less than the first reference voltage(e.g., 1.25V), the comparator CP42 outputs the low level voltage. The ORgate OG generates another low level voltage in response to the low levelvoltage outputted by the comparator, and provides the generated lowlevel voltage to the clock input end of the D flip-flop DFF. The outputend of the D flip-flop DFF remains on the low level voltage based on theoutput of the OR gate OG. At this time, once the capacitor C41discharges to the capacitor voltage below the reference voltage Vref,the output of comparator CP41 is pulled down to the low level voltagewhich represents the end of the pulse on-time (i.e., the fallen edge ofthe pulse). Since the two input ends of the OR gate OG are at the lowlevel voltage, the output end of the OR gate OG also outputs the lowlevel voltage, therefore, the driver DRV generates the disabled controlsignal to cut off the transistor M42 in response to the received lowlevel voltage, so as to cut off the power loop of the LED tube lamp.

As noted above, the operation of the signal processing unit 3420 of thepresent embodiment is similar to that of the detection result latchingcircuit 3220 illustrated in FIG. 16D, the operation of the signalgenerating unit 3410 is similar to that of the detection pulsegenerating module 3210 illustrated in FIG. 16B, the operation of thesignal capturing unit 3430 is similar to that of the detectiondetermining circuit 3230 illustrated in FIG. 16C, and the operation ofthe switch unit 3200 d is similar to that of the switch circuit 3200 billustrated in FIG. 16E.

Referring to FIG. 19A, a block diagram of an installation detectionmodule according to an exemplary embodiment is illustrated. Theinstallation detection module 3000 e includes a detection pulsegenerating module 3510, a control circuit 3520, a detection determiningcircuit 3530, a switch circuit 3200 e, and a detection path circuit3560. The detection determining circuit 3530 is coupled to the detectionpath circuit 3560 via the path 3561 for detecting the signal on thedetection path circuit 3560. The detection determining circuit 3530 iscoupled to the control circuit 3520 via the path 3531 for transmittingthe detection result signal Sdr to the control circuit 3520 via the path3531. The detection pulse generating module 3510 is coupled to thedetection path circuit 3560 via the path 3511 and generates a pulsesignal to inform the detection path circuit 3560 of a time point forconducting the detection path or performing the installation detection.The control circuit 3520 outputs a control signal according to thedetection result signal Sdr and is coupled to the switch circuit 3200 evia the path 3521, so as to transmit the control signal to the switchcircuit 3200 e. The switch circuit 3200 e determines whether to conductthe current path between the installation detection terminals TE1 andTE2 (i.e., part of the power loop). The detection path circuit 3560 iscoupled to the power loop of the power supply module through a firstdetection connection terminal DE1 and a second detection connectionterminal DE2.

In some embodiments, the detection pulse generating module 3510, thecontrol circuit 3520, the detection determining circuit 3530, and thedetection path circuit 3200 e can be referred to a detection circuit oran electric shock detection/protection circuit, which is configured tocontrol the switching state of the switch circuit 3200 e.

In the present embodiment, the configuration of the detection pulsegenerating module 3510 can correspond to the configurations of thedetection pulse generating module 3110 shown in FIG. 15B or thedetection pulse generating module 3210 shown in FIG. 16B. Referring toFIG. 15B, when the detection pulse generating module 3110 is applied toimplement the detection pulse generating module 3510, the path 3511 ofthe present embodiment can correspond to the path 3111, which means theOR gate OG1 is connected to the detection path circuit 3560 via the path3511. Referring to FIG. 16B, when the detection pulse generating module3210 is applied to implement the detection pulse generating module 3510,the path 3511 can correspond to the path 3211. In one embodiment, thedetection pulse generating module is also connected to the outputterminal of the control circuit 3520 via the path 3521, so that the path3521 can correspond to the path 3221.

The control circuit 3520 can be implemented by a control chip or anycircuit capable of performing signal processing. When the controlcircuit 3520 determines the tube lamp is properly installed (e.g., thepins on both ends of the tube lamp are plugged into the lamp socket)according to the detection result signal Sdr, the control circuit 3520may control the switch state of the switch circuit 3200 e so that theexternal power can be normally provided to the LED module when the tubelamp is properly installed into the lamp socket. In this case, thedetection path will be cut off by the control circuit 3520. On thecontrary, when the control circuit 3520 determines the tube lamp is notproperly installed (e.g., a user is touching the pins on one end of thetube lamp with the other end plugged in) according to the detectionresult signal Sdr, the control circuit 3520 keeps the switch circuit3200 e at the off-state since the user has the risk from gettingelectric shock.

In an exemplary embodiment, the control circuit 3520 and the switchcircuit 3200 can be part of the driving circuit in the power supplymodule. For example, if the driving circuit is a switch-type DC-to-DCconverter, the switch circuit 3200 e can be the power switch of theconverter, and the control circuit 3520 can be the controller of thepower switch.

An example of the configuration of the detection determining circuit3530 can be seen referring to the configurations of the detectiondetermining circuit 3130 shown in FIG. 15C or the detection determiningcircuit 3230 shown in FIG. 16C. Referring to FIG. 15C, when thedetection determining circuit 3130 is applied to implement the detectiondetermining circuit 3530, the resistor R14 can be omitted. The path 3561of the present embodiment can correspond to the path 3201, which meansthe positive input terminal of the comparator CP11 is connected to thedetection path circuit 3560. The path 3531 of the present embodiment cancorrespond to the path 3131, which means the output terminal of thecomparator CP11 is connected to the control circuit 3520. Referring toFIG. 16C, when the detection determining circuit 3230 is applied toimplement the detection determining circuit 3530, the resistor R24 canbe omitted. The path 3561 of the present embodiment can correspond tothe path 3201, which means the anode of the diode D21 is connected tothe detection path circuit 3560. The path 3531 of the present embodimentcan correspond to the path 3231, which means the output terminal of thecomparators CP21 and CP22 are connected to the control circuit 3520.

The configuration of the switch circuit 3200 e can correspond to theconfigurations of the switch circuit 3200 a shown in FIG. 15E or theswitch circuit 3200 b shown in FIG. 16E. Since the switch circuit inboth embodiments of FIG. 15E and FIG. 16E are similar to each other, thefollowing description discusses the switch circuit 3200 a shown in FIG.15E as an example. Referring to FIG. 15E, when the switch circuit 3200 ais applied to implement the switch circuit 3200 e, the path 3521 of thepresent embodiment can correspond to the path 3121. The path 3201 is notconnected to the detection determining circuit 3130, but directlyconnected to the installation detection terminal TE2.

Exemplary configurations of the detection path circuit 3560 is shown inFIG. 19B, FIG. 19C or FIG. 19D. Referring to FIG. 19B, the detectionpath circuit 3560 a includes a transistor M51 and resistors R51 and R52.The transistor M51 has a base, a collector, and an emitter. The base ofthe transistor M51 is connected to the detection pulse generating module3510 via the path 3511. The resistor R52 has a first end connected tothe emitter of the transistor M51, and has a second end acting as thesecond detection connection terminal DE2 connected to the groundterminal GND, so the resistor R52 is serially connected between theemitter of the transistor M51 and the ground terminal GND. The resistorR51 has a first end acting as the first detection connection terminalDE1 connected to the first installation detection terminal TE1, whichinstallation detection terminal TE1 is for example connected to thesecond rectifying output terminal 512 in the embodiment of FIG. 19B, sothe resistor R51 is serially connected between the emitter of thetransistor M51 and the installation detection terminal TE1/secondrectifying output terminal 512. Regarding the configured position of thedetection path, the detection path in the embodiment of FIG. 19B is ineffect disposed between a rectifying output terminal and the groundterminal GND.

In the present embodiment, the transistor M51 is conducting during apulse-on period when receiving the pulse signal provided by thedetection pulse generating module 3510. Under the situation where atleast one end of the tube lamp is inserted into the lamp socket, adetection path is formed between the installation detection terminal TE1and the ground terminal (via the resistor R52, the transistor M51, andthe resistor R51) in response to the conducted transistor M51, so as toestablish a voltage signal on the node X of the detection path. In oneembodiment, the detection path is built from one of the rectifyingcircuit input terminals to another one of the rectifying circuit inputterminals (via the rectifying diodes, the resistors R51 and R52, and thetransistor M51). When the user does not touch the tube lamp (but one endof the tube lamp is plugged into the lamp socket) or when the both endsof the tube lamp are plugged into the lamp socket, the signal level ofthe voltage signal is determined by the voltage division of theresistors R51 and R52. When the user touches the tube lamp, a bodyimpedance is equivalent to connect between the resistor R52 and theground terminal GND, which means it is connected to the resistors R51and R52 in series. At this time, the signal level of the voltage signalis determined by the voltage division of the resistor R51, the resistorR52, and the impedance of body impedance. The body impedance refers toan equivalent impedance of human body. The value of the body impedanceis usually between 500 ohm to 2000 ohm, depending on the skin humidity.Accordingly, by setting the resistors R51 and R52 having reasonableresistance, the voltage signal on the node X may reflect or indicate thestate of whether the user touches the tube lamp, and thus the detectiondetermining circuit 3530 may generate the corresponding detection resultsignal Sdr according to the voltage signal on the node X. In addition totemporarily turning on during the detection mode, the transistor M51remains in a cut-off state when the control circuit 3520 determines theLED tube lamp has been correctly installed in the lamp socket, so thatthe power supply module is capable of providing power normally to theLED module.

Referring to FIG. 19C, the detection path circuit 3560 includes thetransistor M52 and the resistors R53 and R54, in which the configurationand operations of an embodiment of the detection path circuit 3560 b inFIG. 19C are largely similar to those in the embodiment of FIG. 19B,with a main difference that the detection path circuit 3560 in FIG. 19Cis disposed between the first rectifying output terminal 511 and thesecond rectifying output terminal 512. In this embodiment, the resistorR53 has a first end (or the first detection connection terminal DE1)connected to the first rectifying output terminal 511, and the resistorR54 has a second end (or the second detection connection terminal DE2)connected to the second rectifying output terminal 512.

In the present embodiment, the transistor M52 is conducting during apulse-on period when receiving a pulse signal provided by the detectionpulse generating module 3510. Under the situation where at least one endof the LED tube lamp is inserted into the lamp socket, a detection pathbetween the first rectifying output terminal 511 and the secondrectifying output terminal 512 of FIG. 14 is conducted through theresistor R53, the transistor M52, and the resistor R54 in response tothe conducted transistor M52, so as to establish a voltage signal on thenode X of the detection path. When the user does not touch the tube lampor when both ends of the tube lamp are correctly plugged into the lampsocket, the signal level of the voltage signal is determined by thevoltage division between the resistors R53 and R54, wherein the seconddetection connection terminal DE2 and the ground terminal GND are at thesame voltage level. When the user touches the tube lamp, some equivalentbody impedance is as connected between the resistor R54/the seconddetection connection terminal DE2 and the ground terminal GND, whichmeans it is connected to the resistors R53 and R54 in series (by thetransistor M52). At this time, the signal level of the voltage signal isdetermined by the voltage division between the resistor R53, theresistor R54, and the equivalent body impedance. Accordingly, by settingappropriate values of the resistors R53 and R54, the voltage signal onthe node X may reflect or indicate the state of whether the user touchesthe LED tube lamp, and thus the detection determining circuit 3530 maygenerate a corresponding detection result signal according to thevoltage signal on the node X. In addition to being temporarily turned onduring the detection mode, the transistor M52 remains in a cut-off statewhen the control circuit 3520 determines the LED tube lamp has beencorrectly installed in the lamp socket, so that the power supply moduleis capable of providing power normally to the LED module.

Referring to FIG. 19D, the detailed configuration and operation of thedetection path circuit 3560 c in the present embodiment are similar tothose of the previous embodiments, and the main difference is that thedetection path circuit 3560 further includes a current limiting elementD51. In some embodiments, the current limiting element D51 can be adiode (hereinafter “diode D51”) disposed between the rectifying outputterminal 511 and the input terminal of the filtering circuit 520 (i.e.,the connection terminal of the capacitor 725 and the inductor 726), asillustrated in FIG. 19D. The filtering circuit 520 includes a pi-type(π-type) filter as an example, but the present invention is not limitedthereto. The addition of the diode D51 can limit the direction ofcurrent on the power loop, so as to prevent the charged capacitor 725from reverse discharging to the detection path during the transistor M51being turned on. Therefore, the accuracy of electric shock detection canbe enhanced. It should be noted that, the configuration of the diode D51is merely an embodiment of the current limiting element. In anotherembodiment, the current limiting element can be implemented byelectronic elements capable of limiting the current direction on thepower loop, the present invention is not limited thereto.

In summary, whether a user is exposed or liable to the risk of electricshock on the LED tube lamp can be determined by conducting a detectionpath and then detecting a voltage signal on the detection path. Inaddition, compared to the above embodiments of FIGS. 15A, 16A, 17A and18A, instead of forming a detection path directly connected to or on apower loop of the power supply module, the detection path circuit 3560illustrated in FIGS. 19A-19D forms/causes an additional detection pathseparate from, independent of, or other than the power loop, i.e., thepower loop and the detection path do not overlap at least partially. Insome embodiments, since the number of electrical components on theseparate detection path is substantially smaller than that of theelectrical components on the power loop, the detected voltage signal onthe additional detection path can reflect more accurately the state ofwhether a user has touched and thus been exposed to the risk of electricshock on part of the LED tube lamp which is not yet correctly installedin the lamp socket.

In some embodiments, the installation detection module 3000 e furtherincludes a ripple detection circuit 3580 configured to provide a flickersuppression function while the LED tube lamp is in a state of normallylighting up. In addition, the switching circuit 3200 e of FIG. 19A maybe disposed as being serially connected to the LED module in the LEDtube lamp, wherein for example one of the installation detectionterminal TE1 and installation detection terminal TE2 is electricallyconnected to a negative terminal of the LED module and the other of thetwo installation detection terminals is electrically connected to aground terminal.

In an installation detection module 3000 e of FIG. 19A having thefunction of flicker suppression, in a detection mode circuit operationsof the detection pulse generating module 3510, the control circuit 3520,the detection determining circuit 3530, the switching circuit 3200 e,and the detection path circuit 3560 of FIG. 19A are respectively similarto those thereof described above, and the control circuit 3520 does notchange its operation state or state of outputting signal in response toa signal output by the ripple detection circuit 3580.

On the other hand, when the LED tube lamp of an installation detectionmodule 3000 e of FIG. 19A having the function of flicker suppressionenters into a normal operation mode, the ripple detection circuit 3580is configured to detect a voltage at the installation detection terminalTE2 and generate and transmit a corresponding signal to the controlcircuit 3520. The control circuit 3520 is then configured to controloperation of the switching circuit 3200 e within a linear region,according to the signal received from the ripple detection circuit 3580,causing an equivalent impedance of the switching circuit 3200 e betweenthe installation detection terminals TE1 and TE2 to vary with themagnitude of the voltage detected by the ripple detection circuit 3580,thereby realizing the effects of maintaining stable luminance andsuppressing flicker phenomenon.

Next, circuit operations of an installation detection module having thefunction of flicker suppression are further described with theembodiment illustrated in FIG. 19E. FIG. 19E is a schematic diagram ofan installation detection module having the function of flickersuppression according to some embodiments. Referring to FIG. 19E, onlymodule(s) and circuit(s) directly related to the function of flickersuppression of the installation detection module are illustrated andexplained below, with other possible structures and configurations ofthe installation detection module similar to those described above withreference to embodiments of FIGS. 19A-19D.

In the present embodiment, the switching circuit 3200 e includes atransistor M53, which is for example but not limited to an N-typeMOSFET. The transistor M53 has a first terminal (such as drain terminal)coupled to a negative terminal of the LED module 50, and has a secondterminal (such as source terminal) coupled through a resistor R55 to asecond driving output terminal 532 (coupled to a ground terminal). Sothe transistor M53 is serially connected between the negative terminalof the LED module 50 and a ground terminal.

When the LED tube lamp enters into a normal operation or lighting mode,the ripple detection circuit 3580 is configured to detect a voltage atthe second terminal of the transistor M53 and then generate and transmita corresponding ripple detection signal to the control circuit 3520.Then the control circuit 3520 outputs a corresponding signal to causethe variation in equivalent impedance of the switching circuit 3200 e tobe positively correlated with the magnitude of voltage detected by theripple detection circuit 3580. For example, when the voltage detected bythe ripple detection circuit 3580 is relatively greater, the controlcircuit 3520 outputs a corresponding signal to cause the equivalentimpedance of the switching circuit 3200 e to be greater; but when thevoltage detected by the ripple detection circuit 3580 is relativelysmaller, the control circuit 3520 outputs a corresponding signal tocause the equivalent impedance of the switching circuit 3200 e to besmaller. Therefore, any ripple current originally arising from voltagefluctuation can be offset or regarded as being absorbed by theequivalent impedance of the switching circuit 3200 e, thereby causing acurrent flowing through the LED module to be substantially maintained inrelatively stable range and thus achieving the effects of flickersuppression.

In summary, in the embodiments of an installation detection moduledescribed above without the function of flicker suppression, under anormal operation mode a control circuit 3520 is configured to output asignal to cause a switching circuit 3200 e to stably operate in asaturation region, so under the normal operation mode the equivalentimpedance of the switching circuit 3200 e substantially does not varywith the variation in voltage between the drain and source terminals ofa transistor in the switching circuit 3200 e, ignoring itschannel-length modulation effects. On the other hand, in the embodimentsof an installation detection module having the function of flickersuppression, under a normal operation mode a control circuit 3520 isconfigured to control a switching circuit 3200 e to operate in a linearregion rather than saturation region, thereby causing the equivalentimpedance of the switching circuit 3200 e to vary with the variation ofa detected voltage, thereby reducing the flicker phenomenon.

FIG. 20A is a block diagram of an installation detection moduleaccording to an exemplary embodiment. Referring to FIG. 20A, theinstallation detection module 3000 f includes a detection pulsegenerating module 3610, a control circuit 3620, a detection determiningcircuit 3630, a switch circuit 3200 f and a detection path circuit 3660.Connection relationship of the detection pulse generating module 3610,the control circuit 3620, the detection determining circuit 3630 and theswitch circuit 3200 f are similar to the embodiment illustrated in FIG.19A, and thus are not repeated herein. The difference between thepresent embodiment and the embodiment of FIG. 19A is the configurationand operation of the detection path circuit 3660. Specifically, thedetection path circuit 3660 has a first detection connection terminalDE1 coupled to a low level terminal of the filtering circuit 520 and asecond detection connection terminal DE2 coupled to the rectifyingoutput terminal 512. In this manner, the detection path circuit 3660 canbe regarded as connecting between the low level terminal of thefiltering circuit 520 and the rectifying output terminal 512. Forexample, the low level terminal of the filtering circuit 520 isconnected to the rectifying output terminal 512 via the detection pathcircuit 3660.

The configuration of the detection path circuit 3660 can be seen in FIG.20B or FIG. 20C, which illustrates a schematic diagram of theinstallation detection module according to some embodiments. Referringto FIG. 20B, the filtering circuit 520 includes, for example, capacitors725 and 727 and an inductor 726, which are configured as a pi-typefilter. The inductor 726 has a first end connected to the rectifyingoutput terminal 511 and a second end connected to the filtering outputterminal 512, which means the inductor 726 is connected between therectifying output terminal 511 and the filtering output terminal 521 inseries. The capacitor 725 has a first end connected to the first end ofthe inductor 726 and a second end connected to the detection pathcircuit 3660. The capacitor 726 has a first end connected to the secondend of the inductor 726 and a second end connected to the second end ofthe capacitor 725, and the second ends of the capacitors 725 and 727 canbe regarded as the low level terminal. The installation detection moduleincludes a detection pulse generating module 3610, a control circuit3620, a detection determining circuit 3630, a switch circuit 3200 f anda detection path circuit 3660. The detection path circuit 3660 includesa resistor R61 and a transistor M61. The transistor M61 has a gateelectrode coupled to the detection pulse generating module 3610, asource electrode coupled a first end of the resistor R61, and a drainelectrode coupled to the second ends of the capacitors 725 and 727. Asecond end of the resistor R61 can be regarded as the second detectionconnection terminal (e.g., DE2) and coupled to the rectifying outputterminal 512 and the first installation detection terminal TE1. Thedetection determining circuit 3630 is coupled to the first end of theresistor R61 to detect magnitude of the current flowing through thedetection path. In the present disclosed embodiment, the detection pathcan be regarded as formed by the capacitors 725 and 727, the inductor726, the resistor R61 and the transistor M61.

In some embodiments, when the transistor M61 receives a pulse signalprovided from the detection pulse generating module 3610, which meansthe LED tube lamp (or power supply module) is under the detection mode,the transistor is turned on during the pulse-on period. Under thecondition that at least one end of the LED tube lamp is correctlyinstalled in the lamp socket, a current path formed, via the detectionpath, between the output rectifying terminals 511 and 512 is conductedin response to the transistor M61 being turned on, and thereforegenerates a voltage signal on the first end of the resistor R61. Whenthere is no person touching the conductive part of the LED tube lamp (orthe LED tube lamp is correctly installed in the lamp socket), a level ofthe voltage signal is determined by the voltage division of theequivalent impedance of the filtering circuit 520 and the resistor R61.When there is a person touching the conductive part of the LED tube lamp(or the LED tube lamp is not correctly installed in the lamp socket), abody impedance is equivalent to serially connect between the seconddetection connection terminal (e.g., DE2) and the ground terminal. Inaddition to temporarily turning on the transistor M61 during thedetection mode, in some embodiments, the transistor M61 further remainsbeing cut off when the control circuit 3620 determines that the LED tubelamp is correctly installed in the lamp socket, so that the power supplymodule can operate normally and provide current to the LED module.

Referring to FIG. 20C, the installation detection module includes adetection pulse generating circuit 3610, a control circuit 3620, adetection determining circuit 3630, a switch circuit 3200 f, and adetection path circuit 3660. The configuration and operation of theinstallation detection module of the present embodiment aresubstantially the same as the embodiment illustrated in FIG. 20B, thedifference between the embodiments of FIGS. 20B and 17C is that thedetection path circuit 3660 of FIG. 20C is disposed between the secondend of the capacitor 725 and the rectifying output terminal 512, and thesecond end of the capacitor 727 is directly connected to the secondinstallation detection terminal TE2 (or second filtering output terminal522).

Compared to the embodiments illustrated in FIG. 19A, since the passivecomponents of the filtering circuit 520 become part of the detectionpath, the current size of the current flowing through the detection pathcircuit 3660 is much smaller than the detection path circuit 3560, andthereby the transistor (e.g., transistor M61 or R61) of the detectionpath circuit 3660 can be implemented by the components with smaller sizeto effectively reduce the cost.

Referring to FIG. 21A, FIG. 21A is a circuit block diagram of a powersupply module of an LED tube lamp according to some embodiments of thepresent disclosure. The power supply module of these embodimentsincludes a rectifying circuit 510, a filtering circuit 520, a drivingcircuit 530 and an installation detection module 3000 g. Theinstallation detection module 3000 g includes a detection controller3100 g, a switch circuit 3200 g and a bias circuit 3300. The detectioncontroller 3100 g includes a control module 3710, an activation controlcircuit 3770 and a detection period determining circuit 3780. Theconfigurations and operations of rectifying circuit 510, filteringcircuit 520, and driving circuit 530 can refer to the descriptions ofthe related above embodiments, and the relevant details are notdescribed herein again.

In installation detection module 3000 g, the switch circuit 3200 g iselectrically connected in series to the power supply loop/power loop ofthe power supply module (in FIG. 21A, the switch circuit 3200 g isdisposed between the rectifying circuit 510 and the filtering circuit520, as an exemplary embodiment), and is controlled by the controlmodule 3710 to switch the turn on/off state. The control module 3710outputs a control signal in a detection mode to temporarily turn on theswitch circuit 3200 g, in order to detect whether an external impedanceis electrically connected to the detection path of the power supplymodule (which means the user may be exposed to an electric shock risk)during the period in which the switch circuit 3200 g is turned on (i.e.,during the period in which the power supply loop/power loop is turnedon/conducted). The detection result determines whether to maintain thedetection mode so that the switch circuit 3200 g is temporarily turnedon in a discontinuous form, or to enter into an operating mode so thatswitch circuit 3200 g responds to the installation status to remainturned-on or cut-off. The length of the period represented by“temporarily turning on the switch circuit” refers to the length of theperiod in which the current on the power loop passes through the humanbody and does not cause any harm to the human body. For example, thelength of the period is less than 1 millisecond. However, the presentdisclosure is not limited thereto. In general, the control module 3710can achieve the operation of temporarily turning on the switch circuit3200 g by transmitting a control signal having pulse waveform. Thespecific duration of the pulse-on period can be adjusted according tothe impedance of the detection path. Descriptions of the circuitconfiguration examples and the related control actions of the controlmodule 3710 and the switch circuit 3200 g can refer to those descriptionof other embodiments related to the installation detection module.

The bias circuit 3300 is electrically connected to the power loop togenerate a driving voltage VCC based on the rectified signal (i.e., thebus voltage). The driving voltage VCC is provided to control module 3710to activate/enable the control module 3710, and for the control module3710 operate in response to the driving voltage.

The activation control circuit 3770 is electrically connected to thecontrol module 3710, and is configured to determine whether to affectthe operating state of control module 3710 according to the outputsignal of detection period determining circuit 3780. For example, whendetection period determining circuit 3780 outputs an enable signal,activation control circuit 3770 will respond to the enable signal andcontrol module 3710 to stop operating when detection period determiningcircuit 3780 outputs a disable signal, activation control circuit 3770will respond to the disable signal and control the control module 3710to maintain a normal operating state (i.e., which does not affect theoperational state of the control module 3710), where activation controlcircuit 3770 can control the control module 3710 to stop operation byusing the driving voltage VCC or providing a low-level start signal tothe enable pin of the control module 3710 However, the presentdisclosure is not limited to these particular examples.

The detection period determining circuit 3780 is configured to samplethe electrical signal on the detection path/power loop, therebycalculating the operation time of the control module 3710, andoutputting a signal indicating the calculation result to activationcontrol circuit 3770, so that activation control circuit 3770 controlsthe operating state of the control module 3710 based on the indicatedthe calculation result.

The operation of installation detection module 3000 g of the embodimentof FIG. 21A is described below. When rectifying circuit 510 receives anexternal power source through pins 501 and 502, bias circuit 3300generates a driving voltage VCC according to the rectified bus voltage.The control module 3710 is activated or enabled in response to thedriving voltage VCC and enters the detection mode. In the detectionmode, control module 3710 periodically outputs a pulse-shaped controlsignal to switch circuit 3200 g, so that switch circuit 3200 g isperiodically turned on and turned off. Under the operation of thedetection mode, the current waveform on the power loop is similar to thecurrent waveform within the detection period Tw in FIG. 41D (i.e., aplurality of spaced-apart current pulses Idp). In addition, detectionperiod determining circuit 3780, upon receiving the bus voltage on thepower loop, starts calculating the operation time of the control module3710 in the detection mode, and outputs a signal indicating thecalculation result to activation control circuit 3770.

In the case when the operation time of the control module 3710 has notreached the preset time length, the activation control circuit 3770 doesnot affect the operating state of the control module 3710. At this time,the control module 3710 determines to maintain the detection mode orenter into the operational mode according to its own detection result.If the control module 3710 determines to enter into the operating mode,the control module 3710 controls the switch circuit 3200 g to remain inthe turn-on state and block the effect of other signals on its operatingstate. In this case, in the operating mode, regardless the output by theactivation control circuit 3770, the operating state of the controlmodule 3710 is not affected.

In the case when the operation time of the control module 3710 hasreached the preset time length, and the control module 3710 is still inthe detection mode, the activation control circuit 3770 controls, inresponse to the output of the detection period determining circuit 3780,the control module 3710 to stop operating. At this time, the controlmodule 3710 no longer outputs a pulse signal, and maintains the switchcircuit 3200 g in the turn-off state until the control module 3710 isreset. The preset time length can be regarded as the detection period Twshown in FIG. 41D.

According to operation described above, the installation detectionmodule 3000 g can let the power supply module have input current (Iin)waveforms as shown in FIG. 41D to 41F by setting the pulse interval andthe reset cycle of the control signal, thereby ensuring that theelectric power in the detection mode is still within a reasonably saferange, to avoid any danger to the human body by the detection current.

From the point of view of circuit operation, the activation controlcircuit 3770 and the detection period determining circuit 3780 can beregarded as a delay control circuit, which is capable of turning on aspecific path, after the LED tube lamp is powered up for a preset delay,to control a target circuit (e.g., the control module 3710). Byselecting the setting of the specific path, a delay conduction for thepower loop or a delay turning-off/cut-off for the installation detectionmodule can be implemented by the delay control circuit in the LED tubelamp.

Referring to FIG. 21B, FIG. 21B is a circuit block diagram of aninstallation detection module for an LED tube lamp according to someembodiments of the present disclosure. The power supply module includesa rectifying circuit 510, a filtering circuit 520, a driving circuit530, and an installation detection module 3000 h. The installationdetection module 3000 h includes a detection controller 3100 h, a switchcircuit 3200 h, and a bias circuit 3300. The detection controller 3100 hincludes a control module 3810, an activation control circuit 3870, anda detection period determining circuit 3880. The configurations andoperations of rectifying circuit 510, filtering circuit 520, and drivingcircuit 530 can refer to the descriptions of the related embodiments. Inaddition, the configurations and operations of control module 3810 andswitch circuit 3200 h can refer to the descriptions of the embodiment ofFIG. 21A above, and details are not described herein again.

In one embodiment, bias circuit 3300 includes a resistor R71, acapacitor C71, and a Zener diode ZD1. The first end of resistor R71 iselectrically connected to the rectified output terminal (i.e.,electrically connected to the bus). Capacitor C71 and Zener diode ZD1are electrically connected in parallel with each other, and their firstends are both electrically connected to the second end of resistor R71.The power input terminal of control module 3810 is electricallyconnected to a common node of resistor R71, capacitor C71, and Zenerdiode ZD1 (i.e., the bias node of bias circuit 3300) to receive thedriving voltage VCC on the common node.

Activation control circuit 3870 includes a Zener diode ZD2, a transistorM71, and a capacitor C72. The anode of Zener diode ZD2 is electricallyconnected to the control terminal of transistor M71. The first end oftransistor M71 is electrically connected to control module 3810, and thesecond end of transistor M71 is electrically connected to the groundterminal GND. Capacitor C72 is electrically connected between the firstend and the second end of transistor M71.

Detection period determining circuit 3880 includes a resistor R72, adiode D71, and a capacitor C73. The first end of resistor R72 iselectrically connected to the bias node of bias circuit 3300, and thesecond end of resistor R72 is electrically connected to the cathode ofZener diode ZD2. The anode of diode D71 is electrically connected to thesecond end of resistor R72, and the cathode of diode D71 is electricallyconnected to the first end of resistor R72. The first end of capacitorC73 is electrically connected to the second end of resistor R72 and theanode of diode D71, and the second end of capacitor C73 is electricallyconnected to the ground terminal GND.

The operation of installation detection module 3000 h of the embodimentof FIG. 21A is described below. When rectifying circuit 510 receives anexternal power source through pins 501 and 502, the rectified busvoltage charges capacitor C71, thereby establishing a driving voltageVCC at the bias node. Control module 3810 is enabled in response to thedriving voltage VCC and enters into the detection mode. In the detectionmode, in the first signal cycle, control module 3810 outputs apulse-shaped control signal to the switch circuit 3200 h, so that theswitch circuit 3200 h is temporarily turned on and then cut off.

During the switch circuit 3200 h being turned-on, the capacitor C73 ischarged in response to the driving voltage VCC on the bias node, suchthat the voltage across capacitor C73 gradually rises. In the firstsignal period, because the increased voltage across capacitor C73 hasnot reached the threshold level of transistor M71, transistor M71 willremain in the off state. As a result, the enable signal Ven ismaintained at a high level accordingly. Then, during the switch circuit3200 h being turned-off or cut-off, capacitor C73 will substantiallymaintain the voltage level or slowly discharge, wherein the voltagechange caused by the discharge of capacitor C73 during the switchcircuit being turned-off is less than that caused by the charging duringthe switch circuit being turned-on. In other words, the voltage acrosscapacitor C73 during the switch being turned off will be less than orequal to the highest voltage level during the switch being turned on,and the lowest voltage level will not be lower than its initial level atthe charging start point, so transistor M71 will always remain in theoff state in the first signal period, and the start signal Ven ismaintained at a high level. Control module 3810 is maintained in anenabled state in response to a high level enable signal Ven. In theenabled state, control module 3810 determines whether the LED tube lampis correctly installed according to the signal on the detection path(i.e., determines whether there is additional impedance is introduced).The installation detection mechanism of this part is the same as theprevious embodiment, and details are not further described herein.

When control module 3810 determines that the LED tube lamp has not beenproperly installed to the socket, control module 3810 maintains thedetection mode and continuously outputs a pulse-shaped control signal tocontrol switch circuit 3200 h. In the following signal periods,activation control circuit 3870 and detection period determining circuit3880 continue to operate in a manner similar to the operation of thefirst signal period. Specifically, capacitor C73 is charged during theon period of each signal period, so that the voltage across capacitorC73 rises step by step in response to the pulse width and the pulseperiod. When the voltage across capacitor C73 exceeds the thresholdlevel of transistor M71, transistor M71 is turned on so that the enablesignal Ven is pulled down to the ground level/low level. At this time,control module 3810 is turned off in response to the low level enablesignal Ven. When control module 3810 is turned off, switch circuit 3200h is maintained in turn-off/cut-off state regardless of whether or notan external power source is electrically connected.

When the control module 3810 determines that the LED tube lamp has beenproperly installed in the lamp socket, the control module 3810 enters anoperational mode and outputs a control signal to maintain the switchcircuit 3200 h in a turn-on state. In the operating mode, the controlmodule 3810 does not change the output control signal in response to theenable signal Ven. In other words, even if the enable signal Ven ispulled down to a low level, the control module 3810 does not turn offswitch circuit 3200 h again.

From the point of view of the multiple signal periods in the detectionmode, the current waveform measured on the power loop is as shown inFIG. 41D, in which the period of capacitor C73 charged from the initiallevel to the threshold level of transistor M71 corresponds to thedetection period Tw. In other words, in the detection mode, controlmodule 3810 continues outputting pulse signal until capacitor C73 ischarged to the threshold level of transistor M71, resulting inintermittent current in the power loop. And when the voltage acrosscapacitor C73 exceeds the threshold, the pulse signal is stopped toavoid any danger to the human body by the increased electric power inpower loop.

From another perspective, the detection period determining circuit 3880can be regarded as calculating the pulse-on period of the calculationcontrol signal. When the preset value is reached during the pulse-onperiod, the control signal is sent out to control activation controlcircuit 3870, then activation control circuit 3870 affects the operationof control module 3810 to block the pulse output.

In the circuit architecture of this embodiment, the length of thedetection period Tw (i.e., the time required for capacitor C73 to reachthe threshold voltage of transistor M71) is mainly controlled byadjusting the capacitance value of capacitor C73. The main function ofthe components such as resistor R72, diode D71, Zener diode ZD2, andcapacitor C72 is to support activation control circuit 3870 anddetection period determining circuit 3880 to provide voltage stability,voltage limit, current limit, or protection.

Referring to FIG. 21C, FIG. 21C is a circuit diagram of an installationdetection module for a LED tube lamp according to some embodiments ofthe present disclosure. The power supply module of the embodimentincludes rectifying circuit 510, filtering circuit 520, driving circuit530, and an installation detection module 3000 i. Installation detectionmodule 3000 i includes a detection controller 3100 i, a switch circuit3200 i, and a bias circuit 3300. The detection controller 3100 iincludes a control module 3910, an activation control circuit 3970 and adetection period determining circuit 3980. The configurations andoperations of rectifying circuit 510, filtering circuit 520, and drivingcircuit 530 can refer to the descriptions of the related embodiments. Inaddition, the configurations and operations of control module 3910 andswitch circuit 3200 i can refer to the descriptions of the embodiment ofFIG. 21A mentioned above, and the details are not described hereinagain.

Bias circuit 3300 includes a resistor R81, a capacitor C81, and a Zenerdiode ZD3. The first end of resistor R81 is electrically connected tothe rectified output (i.e., electrically connected to the bus).Capacitor C81 and Zener diode ZD3 are electrically connected in parallelwith each other, and their first ends are both electrically connected tothe second end of resistor R81. The power supply input of control module3910 is electrically connected to a common node of resistor R81,capacitor C81, and Zener diode ZD3 (i.e., the bias node of bias circuit3300) to receive the driving voltage VCC.

Activation control circuit 3970 includes a Zener diode ZD4, a transistorM81, and resistors R82 and R83. The anode of Zener diode ZD2 iselectrically connected to the control terminal of transistor M81. Thefirst end of resistor R82 is electrically connected to the anode ofZener diode ZD4 and the control terminal of transistor M81, and thesecond end of resistor R82 is electrically connected to the groundterminal GND. The first end of transistor M81 is electrically connectedto the bias node of bias circuit 3300 through a resistor R83, and thesecond end of transistor M81 is electrically connected to the groundterminal GND.

Detection period determining circuit 3980 includes a diode D81,resistors R84 and R85, a capacitor C82, and a Zener diode 3775. Theanode of diode D81 is electrically connected to one end of switchcircuit 3200 i, which can be regarded as the detecting node of detectionperiod determining circuit 3980. The first end of resistor R84 iselectrically connected to the cathode of diode D81, and the second endof resistor R84 is electrically connected to the cathode of Zener diodeZD4. The first end of resistor R85 is electrically connected to thesecond end of resistor R84, and the second end of resistor R85 iselectrically connected to the ground terminal GND. Capacitor C82 andZener diode ZD5 are both electrically connected in parallel withresistor R85, wherein the cathode and the anode of Zener diode ZD5 areelectrically connected to the first end and the second end of resistorR85 respectively.

The operation of the installation detection module 3000 i of thisembodiment is described below. When rectifying circuit 510 receives anexternal power source through pins 501 and 502, the rectified busvoltage charges capacitor C81, thereby establishing a driving voltageVCC at the bias node. Control module 3910 is enabled in response to thedriving voltage VCC and enters the detection mode. In the detectionmode, in the first signal cycle, control module 3910 sends apulse-shaped control signal to switch circuit 3200 i, so that switchcircuit 3200 i is temporarily turned on and then turned off.

During the period that switch circuit 3200 i is turned on, the anode ofdiode D81 can be regarded as electrically connected to ground, socapacitor C82 is not charged. During the first signal period, thevoltage across capacitor C82 will remain at the initial level during theswitch circuit 3200 i being turned on, and transistor M81 will remain inthe turn-off/cut-off state, and thus will not affect the operation ofcontrol module 3910. Next, during the switch circuit 3200 i being turnedoff/cut off, the power loop causes the voltage level on the detectingnode to rise in response to the external power supply, wherein thevoltage applied to the capacitor C82 is equal to the voltage division ofthe resistors R84 and R85. Therefore, during the period that the switchcircuit 3200 i is turned off, the capacitor C82 is charged in responseto the voltage division of resistors R84 and R85, and the voltage acrossthe capacitor C82 gradually rises. During the first signal period,because the increased voltage across the capacitor C82 has not reachedthe threshold level of the transistor M81, the transistor M81 remains inan off state, so that the driving voltage VCC remains unchanged. Sincethe transistor M81 remains in the off state during the first signalperiod no matter whether the switch circuit 3200 i is turned on or cutoff, the driving voltage VCC is not affected. Therefore, control module3910 is maintained in the enabled or activated state in response to thedriving voltage VCC. In the activated state, control module 3910determines whether the LED tube lamp is correctly installed according tothe signal on the detection path (i.e., determines whether an externalimpedance is introduced). The installation detection mechanism of thispart is the same as the previous embodiment, and details are notdescribed herein again.

When control module 3910 determines that the LED tube lamp has not beenproperly installed to the socket, control module 3910 maintains thedetection mode and continuously outputs a pulse-shaped control signal tocontrol switch circuit 3200 i. In the following signal periods,activation control circuit 3970 and detection period determining circuit3980 continue to operate in a manner similar to the operation of thefirst signal period. That is, capacitor C82 is charged during the offperiod of each signal period, so that the voltage across capacitor C82rises step by step in response to the pulse width and the pulse period.When the voltage across capacitor C82 exceeds the threshold level oftransistor M81, transistor M81 is turned on causing the bias node to beshorted to the ground terminal GND, thereby causing the driving voltageVCC to be pulled down to the ground/low voltage level. At this time, thecontrol module 3910 is disabled or deactivated in response to thedriving voltage VCC of the low voltage level. When the control module3910 is disabled or deactivated, the switch circuit 3200 i is maintainedin an off state regardless of whether or not an external power source iselectrically connected.

When the control module 3910 determines that the LED tube lamp has beenproperly installed in the lamp socket, the control module 3910 willenter an operating mode and issue a control signal to maintain theswitch circuit 3200 i in a conductive state or turn-on state. In theoperating mode, since the switch circuit 3200 i remains turned on, thetransistor M81 is maintained in an off state, so that the drivingvoltage VCC is not affected, and the control module 3910 can operatenormally.

From the point of view of the multiple signal periods in the detectionmode, the current waveform measured on the power loop is as shown inFIG. 41D, in which the period of capacitor C82 charged from the initiallevel to the threshold level of transistor M81 corresponds to thedetection period Tw. In other words, in the detection mode, controlmodule 3910 continues outputting pulse signal until capacitor C82 ischarged to the threshold level of transistor M81, resulting inintermittent current in the power loop. And when the voltage acrosscapacitor C82 exceeds the threshold, the pulse signal is stopped toavoid any danger to human body by the increased electric power in powerloop.

From another perspective, the detection period determining circuit 3980is in effect used to calculate the pulse-off period of the controlsignal, and when the calculated pulse-off period has reached a presetvalue, then to output a signal to control the activation control circuit3970, causing the activation control circuit 3970 to affect operation ofthe control module 3910 so as to block or stop outputting of the pulsesignal.

In the circuit architecture, the length of the detection period Tw(i.e., the time required for capacitor C82 to reach the thresholdvoltage of transistor M81) is mainly controlled by adjusting thecapacitance value of capacitor C82 and resistance values of resistorsR84, R85, and R82. Components such as diode D81, Zener diodes ZD5 andZD4, and resistor R83 are used to assist in the operations of activationcontrol circuit 3970 and the detection period determining circuit 3980to provide the function of voltage stabilization, voltage limiting,current limiting, or protection.

Referring to FIG. 21D, FIG. 21D is a circuit diagram of an installationdetection module for an LED tube lamp according to some embodiments ofthe present disclosure. The power supply module of the embodimentincludes rectifying circuit 510, filtering circuit 520, driving circuit530, and installation detection module 3000 j. Installation detectionmodule 3000 j includes detection controller 3100 j, switch circuit 3200j, and bias circuit 3300. The detection controller 3100 j includescontrol module 3910, activation control circuit 3970, and detectionperiod determining circuit 3980. In the present embodiment, theconfigurations and operations of installation detection module 3000 j isalmost the same as these of the embodiment of FIG. 21C. The maindifference between FIGS. 21C and 21D is that detection perioddetermining circuit 3980 of the present embodiment in FIG. 21D includesnot only diode D81, resistors R84 and R85, capacitor C82 and Zener diodeZD5, but also resistors R86, R87 and R88 and diode D82. Resistor R86 isdisposed in series between diode D81 and resistor R84. The first end ofresistor R87 is electrically connected to the first end of resistor R84,and the second end of resistor R87 is electrically connected to thecathode of Zener diode ZD4. Resistor R88 and capacitor C82 areelectrically connected in parallel with each other. The anode of diodeD82 is electrically connected to the first end of capacitor C82 and thecathode of Zener diode ZD4, and the cathode of diode D82 is electricallyconnected to the second end of resistor R84 and the first end ofresistor R85.

In the circuit architecture of this embodiment, the circuit for chargingcapacitor C82 is changed from resistors R84 and R85 to resistors R87 andR88. Capacitor C82 is charged based on the voltage division of resistorsR87 and R88. Specifically, the voltage on the detecting node firstgenerates a first-order partial voltage on the first end of resistor R84based on the voltage division of resistors R86, R84, and R85, and thenthe first-order partial pressure generates a second order partialvoltage at the first end of capacitor C82 based on the voltage divisionof resistors R87 and R88. In this configuration, the charging rate ofcapacitor C82 can be controlled by adjusting the resistance values ofresistors R84, R85, R86, R87, and R88, and not limited by just adjustingcapacitor value. As a result, the size of capacitor C82 can beeffectively reduced. On the other hand, since resistor R85 is no longerworking as a component on the charging circuit, a smaller resistancevalue can be selected, so that the discharging rate of capacitor C82 canbe increased, thereby the reset time for the detection perioddetermining circuit 3980 can be reduced.

Although the modules/circuits are named by their functionality in theembodiments described in the present disclosure, it should be understoodby those skilled in the art that the same circuit component may beconsidered to have different functions based on the circuit design anddifferent modules/circuits may share the same circuit component toimplement their respective circuit functions. Thus, the functionalnaming of the present disclosure is not intended to limit a particularunit, circuit, or module to particular circuit components.

For example, the installation detection module of the above embodimentsmay be alternatively referred to as a detection circuit/module, aleakage current detection circuit/module, a leakage current protectioncircuit/module, an impedance detection circuit/module, or genericallyreferred to as circuitry. The detection result latching module of theabove embodiments may be alternatively referred to as a detection resultstorage circuit/module, or a control circuit/module. And the detectioncontroller of the above embodiments may be a circuit including thedetection pulse generating module, the detection result latching module,and the detection determining circuit, although the present invention isnot limited to such a circuit of detection controller.

FIG. 22A is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments. Referring to FIG.22A, the installation detection module 3000 k has a circuitconfiguration for continuously detecting the signal on the power loop.The installation detection module 3000 k includes the control circuit3020, the detection determining circuit 3030 and the current limitingcircuit 3200 k. The control circuit 3620 is configured to control thecurrent limiting circuit 3200 k according to the detection resultgenerated by the detection determining circuit 3030, so that the currentlimiting circuit 3200 k determines whether to perform the currentlimiting operation, for limiting the current on the power loop, based onthe control of the control circuit 3020. In the present embodiment, thecontrol circuit 3020 is preset to not perform the current limitingoperation, which means the current on the power loop is not limited bythe current limiting circuit 3200 k at the preset state. Therefore,under the preset state, as long as the external AC power source isconnected to the LED tube lamp, the input power can be provided to theLED module 50 through the power loop.

The following description describes the operation of detecting thesignal on the power loop for example, but the invention is not limitedthereto. In detail, when the external AC power source connects to theLED tube lamp, the input power enables the detection determining circuit3030 for starting to detect the signal on a specific node of the powerloop, and the detection result is transmitted to the control circuit3020. The control circuit 3020 determines whether the conductive part istouched by a user according to at least one signal feature, such as thevoltage/current level, the waveform, the frequency and other features,of the detection result signal. When the control circuit 3020 determinesthe LED tube lamp is touched by a user according to the detection resultsignal, the control circuit 3020 controls the current limiting circuit3200 k to perform the current limiting operation, so that the current onthe power loop is limited to lower than a predetermined value, andtherefore the occurrence of electric shock can be prevented/avoided.

FIG. 22B is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments. Referring to FIG.22B, the installation detection module 3000L of the present embodimentis substantially the same as the installation detection module 3000 k.The difference is the installation detection module 3000L has a circuitconfiguration for continuously detecting the signal on the detectionpath. The installation detection module 3000L includes a control circuit3020, a detection determining circuit 3030, a current limiting circuit3200L and a detection path circuit 3060. The operation of the controlcircuit 3020, detection determining circuit 3030 and the currentlimiting circuit 3200L can be referred to in connection with theembodiments of FIG. 22A, and it will not be repeated herein.

The detection path circuit 3060 can be disposed on the input side or theoutput side of one of the rectifying circuit 510, the filtering circuit520, the driving circuit 530 and the LED module 50, and the presentinvention is not limited thereto. In addition, in the practicalapplication, the detection path circuit 3060 can be implemented by anycircuit structure capable of responding the impedance variation causedby the human body. For example, the detection path circuit 3060 can beformed by at least one passive component (e.g., resistor, capacitor,inductor), at least one active component (e.g., MOSFET, siliconcontrolled rectifier (SCR)) or the combination of the above.

In summary, the power supply modules illustrated in FIGS. 22A and 22Bare configured in a continuous detection setting, which refers to thepower supply module having a circuit (e.g., the installation detectionmodule 3000 k/3000L) for continuously detecting the installation stateor the risk of electric shock. In some embodiments, under the continuousdetection setting, the power loop/detection path is preset to be in aconducting state or a non-limiting state, and the current on the powerloop would not be limited until the incorrect installation state or therisk of electric shock (the LED tube lamp is touched by a user) isdetected.

Some embodiments of the power supply module are configured in a pulsedetection setting, which refers to the power supply module having acircuit (e.g., the installation detection module 3000) for detecting theinstallation state or the risk of electric shock in certain duration(e.g., the pulse-on period). For example, under the pulse detectionsetting, the power loop/detection path is preset to be in anon-conducting state or a current limiting state. Before confirming theinstallation state or the risk of electric shock, the powerloop/detection path is only turned on when the pulse-on period occurs.In addition, the current on the power would be limited until the correctinstallation state or no risk of electric shock (the LED tube lamp isnot touched by a user) is detected. From the perspective of the currentlimiting circuit such as the switch circuit 3200, 3200 a-L, the currentlimiting circuit being disabled refers to the current limiting circuitnot limiting the current on the power loop, which causes the power loopto be in the conducting state or the non-limiting state. On the otherhand, the current limiting circuit being enabled refers to the currentlimiting circuit limiting the current on the power loop, which causesthe power loop to be in the non-conducting state or the current limitingstate.

In some embodiments, the continuous detection setting can beindependently used for implementing the installation detection and theelectric shock protection mechanism.

In some embodiments, the continuous detection setting and the pulsedetection setting can be used together for implementing the installationdetection and the electric shock protection mechanism. For example, theLED tube lamp can utilize the pulse detection setting before the LEDmodule is lighted up and can then change to the continuous detectionsetting during the LED tube lamp emitting light.

From the perspective of the circuit operation, the switching of thepulse detection setting and the continuous detection setting can bedetermined based on the current on the power loop. For example, when thecurrent on the power loop is smaller than the predetermined value (e.g.,5 MIU), the installation detection module enables the pulse detectionsetting. If the current on the power loop is detected to be greater thanthe predetermined value, the installation detection module changes toenable the continuous detection setting. From the perspective of theoperation and the installation of the LED tube lamp, the installationdetection module is preset to enable the pulse detection setting, sothat the installation detection module utilizes the pulse detectionsetting for detecting the installation state (or the risk of electricshock) and performing the electric shock protection when the LED tubelamp is powered up. As long as the correct installation state isdetected, the installation detection module changes to utilize thecontinuous detection setting for detecting whether the conductive partof the LED tube lamp is touched by a user during the LED tube lampemitting light. In addition, the installation detection module will bereset to the pulse detection setting if the LED tube lamp is poweredoff.

With respect to hardware configuration of the LED tube lamp system, nomatter whether the installation detection module is disposed inside theLED tube lamp (as shown in FIG. 13A) or externally on the lampsocket/fixture (as shown in FIG. 13B), a designer according to needs canselectively apply the continuous detection setting or the pulsedetection setting in the LED tube lamp system. In this manner, no matterwhether the installation detection module 3000 is configured inside theLED tube lamp or externally on the lamp socket, the installationdetection module 3000 can perform installation detection and electricshock protection of the LED tube lamp, according to the abovedescription of various embodiments.

A difference between internally disposing an installation detectionmodule and externally disposing an installation detection module is thatthe first installation detection terminal TE1 and the secondinstallation detection terminal TE2 of the external installationdetection module are connected to and between an external power grid anda conductive pin of the LED tube lamp, for example, the firstinstallation detection terminal TE1 and the second installationdetection terminal TE2 are serially connected on a signal line of theexternal driving signal; and they are electrically coupled to the powerloop of the LED tube lamp through the conductive pins. In anotherrespect, although not shown in the described figures, a person ofordinary skill in the art can understand that in some embodiments of theinstallation detection module of this disclosure, the installationdetection module may have or include a bias circuit for generating adriving voltage configured to provide power for operations of circuitsin the installation detection module.

The embodiments of the installation detection module illustrated in FIG.15A, FIG. 16A, FIG. 17A, FIG. 18A, FIG. 19A, FIG. 20A and FIG. 21A teachthe installation detection module includes a pulse generating mechanismsuch as the detection pulse generating modules 3110,3210, and 3510, thepulse generating auxiliary circuit 3310, and the signal generating unit3410 for generating a pulse signal, however, the present invention isnot limited thereto. In an exemplary embodiment, the installationdetection module can use the original clock signal in the power supplymodule to replace the function of the pulse generating mechanism in theabove embodiments. For example, in order to generate a lighting controlsignal having a pulse waveform, the driving circuit (e.g., DC-to-DCconverter) in the power supply module has a reference clock, originally.The function of the pulse generating mechanism can be implemented byusing the reference clock of the lighting control signal as a reference,so that the hardware of the detection pulse generating module 3110,3210, 3510/pulse generating auxiliary module 3310/signal generating unit3410 can be omitted. In this case, the installation detection module canshare the circuit configuration with another part of the circuit in thepower supply module, so as to realize the function of generating thepulse signal. In addition, the duty cycle of the pulse generatingmechanism can be any value in the interval of a real number greater than0 to 1, in which the duty cycle equal to 0 means the power loop isnormally closed, and the duty cycle equal to 1 means the power loop isnormally open.

In some embodiments, when the duty cycle is set to smaller than 1, thedetection operation of the installation detection module is performed bytemporarily conducting a current on the power loop/detection path anddetecting a signal on the power loop/detection path to obtain theinstallation state of the LED tube lamp without causing electric shock.When the LED tube lamp is correctly installed in the lamp socket (i.e.,the pins on the both end caps are correctly connected to the connectingsockets), the current limiting module is disabled for conducting thedriving current on the power loop, so as to drive/light up the LEDmodule. Under such configuration, the current limiting module is presetto be in an enable state, so that the power loop can be maintained inthe non-conducting state before confirming whether there is the risk ofelectric shock (or whether the LED tube lamp is correctly installed).The current limiting module is switched to a disable state when the LEDtube lamp is correctly installed. Taking the switch circuit for example,the enable state of the current limiting module refers to the switchcircuit being cut-off, and the disable state of the current limitingmodule refers to the switch circuit being turned on. Such configurationcan be referred to as a pulse detection setting (the duty cycle isgreater than 0 and smaller than 1). Under the pulse detection setting,the installation detection means performs during the pulse-on period ofeach pulse after powering up, and the electric shock protection means isimplemented by suspending the current flowing through the power loopuntil the correct installation state is detected or the risk of electricshock is excluded.

In some embodiments, when the duty cycle is set to equal to 1, thedetection operation of the installation detection module is performed bycontinuously monitoring/sampling the signal on the power loop/detectionpath. The sample signal can be used for determining the equivalentimpedance of the power loop/detection path. When the equivalentimpedance indicates there is a risk of electric shock (i.e., a usertouches the conductive part of the LED tube lamp), the current limitingmodule is switched to be in the enable state for cutting off the powerloop. Under such configuration, the current limiting module is preset tobe in the disable state, so that the power loop can be maintained in theconducting/non-limiting state before confirming whether there is therisk of electric shock (or whether the LED tube lamp is correctlyinstalled), in which case the LED tube lamp can be lighted up in thepreset condition. The current limiting module is switched to the enablestate when the risk of electric shock is detected. Such configurationcan be referred to a continuous detection setting (the duty cycle equalsto 1). Under the continuous detection setting, the installationdetection means performs continuously without considering whether theLED tube lamp is lighted up or not, after powering up, and the electricshock protection means is implemented by allowing the current to flowthrough the power loop until the incorrect installation state or therisk of electric shock is detected. Either the incorrect installationstate or the risk of electric shock being detected can be referred to anabnormal state.

Specifically, the risk of electric shock may occur as long as one end ofthe LED tube lamp is connected to the external power. Therefore, nomatter whether installing or removing the LED tube lamp, once the usertouches the conductive part of the tube lamp, the user is exposed to therisk of electric shock. In order to avoid the risk of electric shock, nomatter whether the LED tube lamp is lighted up or not, the installationdetection module operates based on the pulse detection setting or thecontinuous detection setting to detect the installation state and theuser touching state and protect the user from being electricallyshocked. Therefore, the safety of the LED tube lamp can be furtherimproved.

Under the continuous detection setting, the pulse generating mechanismcan be referred to as a path enabling mechanism, which is configured toprovide a conduction signal for turning on the power loop/detectionpath. In some embodiments, for circuit structures of the detection pulsegenerating modules 3110, 3210 and 3510, the pulse generating auxiliarymodule 3310 and signal generating unit 3410 can be correspondinglymodified to a circuit for providing fixed voltage. In addition, theswitch circuits 3200, 3200 a-L, can be modified to be preset to be inthe conducting state/turn-on state, and to switch to the non-conductingstate/cut-off state when the risk of electric shock is detected (it canbe implemented by modifying the logic gate of the detection resultlatching circuit). In some embodiments, the circuit for generating apulse can be omitted by modifying the circuit structure of the detectiondetermining circuit and the detection path circuit. For example, underthe continuous detection setting, the detection pulse generating module3110 in the installation detection module of FIG. 15A and the detectionpulse generating module 3210 in the installation detection module ofFIG. 16A can be omitted, and so on. In addition, according to theembodiment of disposing the additional detection path in theinstallation detection module, the detection pulse generating module3510 can be omitted if the continuous detection setting is applied, andthe detection path circuit 3560 is maintained in the conducting state(e.g., the transistor M51 is omitted).

FIG. 23 is a circuit block diagram of a power supply module in an LEDtube lamp according to some embodiments. Referring to FIG. 23, the LEDtube lamp 1200 is, for example, configured to receive an externaldriving signal directly provided by an external AC power source 508,wherein the external driving signal is input through the live wire(marked as “L”) and the neutral wire (marked as “N”) to two pins 501 and502 on two ends of the LED tube lamp 1200. In practical applications,the LED tube lamp 1200 may further have two additional pins 503 and 504,also on the two ends. Under the structure of the LED tube lamp 1200having the four pins 501-504, depending on design requirements two pins(such as the pins 501 and 503, or the pins 502 and 504) on an end capcoupled to one end of the LED tube lamp 1200 may be electricallyconnected or mutually electrically independent, but the invention is notlimited to any of the mentioned cases. An electric-shock detectionmodule 4000 is disposed inside the LED tube lamp 1200 and includes adetection control circuit 4100 and a current-limiting circuit 4200. Theelectric-shock detection module 4000 may be and is hereinafter referredto as an installation detection module 4000. The current-limitingcircuit 4200 is coupled to a rectifying circuit 510 through a firstinstallation detection terminal TE1 and coupled to a filtering circuit520 through a second installation detection terminal TE2, so is seriallyconnected on a power loop in the LED tube lamp 1200. Under a detectionmode, the detection control circuit 4100 is configured to detect asignal on an input side of the rectifying circuit 510 such as an inputsignal provided by the external AC power source 508, and configured todetermine whether to prevent a current from passing through the LED tubelamp 1200 according to the detection result. When the LED tube lamp 1200is not yet correctly/properly installed into a lamp socket, thedetection control circuit 4100 detects a relatively small current signaland then assumes/presumes it to be facing or passing through relativelyhigh impedance, so the current-limiting circuit 4200 in response cutsoff a current path between the first installation detection terminal TE1and second installation detection terminal TE2 to prevent the LED tubelamp 1200 from operating (i.e., suspending the LED tube lamp 1200 fromlighting up). On the other hand, when a relatively large current signalis detected or a relatively small current signal is not detected, thedetection control circuit 4100 determines that the LED tube lamp 1200 iscorrectly/properly installed into a lamp socket, and then thecurrent-limiting circuit 4200 causes or allows the LED tube lamp 1200 tooperate in a normal lighting mode (i.e., allowing the LED tube lamp 1200being lighted up) by maintaining current conduction between the firstinstallation detection terminal TE1 and second installation detectionterminal TE2. In some embodiments, when a current signal passing on theinput side of the rectifying circuit 510 sampled and detected by thedetection control circuit 4100 is equal to or higher than a defined orset current value, the detection control circuit 4100 determines thatthe LED tube lamp 1200 is correctly/properly installed into a lampsocket and then causes the current-limiting circuit 4200 to conductcurrent, thereby causing the LED tube lamp 1200 to operate in a normallighting mode. When the current signal is lower than a defined or setcurrent value, the detection control circuit 4100 determines that theLED tube lamp 1200 is not correctly/properly installed into a lampsocket and thus cuts off the current-limiting circuit 4200 or a currentpath thereof, thereby causing the LED tube lamp 1200 to enter into anon-conducting state or limiting an effective current value on a powerloop in the LED tube lamp 1200 to being smaller than, for example, 5 mA(or 5MIU according to certain certification standards). In other words,the installation detection module 4000 can be regarded as determiningwhether to allow or limit current conduction based on the detectedimpedance, thereby causing the LED tube lamp 1200 to operate in aconducting state or enter into a cutoff or current-limited state.Accordingly, the LED tube lamp 1200 using such an installation detectionmodule 4000 has the benefit of avoiding or reducing the risk of electricshock hazard occurring on the body of a user when accidentally touchingor holding a conducting part of the LED tube lamp 1200 which is not yetcorrectly/properly installed into a lamp socket.

Specifically, when (part of) a human body touches or contacts the LEDtube lamp, impedance of the human body may cause a change in equivalentimpedance on a power loop in the LED tube lamp, so the installationdetection module 4000 of FIG. 23 can determine whether a human body hastouched or contacted the LED tube lamp by e.g., detecting a change incurrent/voltage on the power loop, in order to implement the function ofelectric-shock prevention. The installation detection module 4000 of thepresent embodiment can determine whether the LED tube lamp 1200 iscorrectly/properly installed into a lamp socket or whether the body of auser has accidentally touched a conducting part of the LED tube lampwhich is not yet correctly/properly installed into a lamp socket, bydetecting an electrical signal such as a voltage or current. Further,compared to the embodiment of FIG. 14, since a signal used fordetermining the installation state is detected/sampled, by the detectioncontrol circuit 4100, from the input side of the rectifying circuit 510,the signal characteristics may not be easily influenced by othercircuits in the power supply module, so that the possibility ofmisoperation of the detection control circuit 4100 can be reduced.

From circuit operation perspectives, a method performed by the detectioncontrol circuit 4100 and configured to determine, under a detectionmode, whether the LED tube lamp 1200 is correctly/properly installed toa lamp socket or whether there is any unintended external impedancebeing connected to the LED tube lamp 1200 is shown in FIG. 44A. Themethod includes the following steps: temporarily conducting a detectionpath for a period and then cutting it off (step S101); sampling anelectrical signal on the detection path during the conduction period(step S102); determining whether the sample of electrical signalconforms with predefined signal characteristics (step S103); if thedetermination result in step S103 is positive, controlling thecurrent-limiting circuit 4200 to operate in a first state (step S104);and if the determination result in step S103 is negative, controllingthe current-limiting circuit 4200 to operate in a second state (stepS105) and then returning to the step S101.

In the method of FIG. 44A performed in the embodiment of FIG. 23, thedetection path can be a current path connected between the input side ofthe rectifying circuit 510 and a ground terminal, and its detailedcircuit configurations in the embodiment are presented and illustratedbelow with reference to FIGS. 24A and 24B. In addition, the detaileddescription of how to set parameters such as the conduction period,intervals between multiple conduction periods, and the time point totrigger conduction, of the detection path in the detection controlcircuit 4100 can refer to the relevant embodiments described in thedisclosure.

In the step S101, conducting the detection path for a period may beimplemented by means using pulse signal to control switching of aswitch.

In the step S102, the sample of electrical signal is a signal that canrepresent or express impedance variation on the detection path, whichsignal may comprise a voltage signal, a current signal, a frequencysignal, a phase signal, etc.

In the step S103, the operation of determining whether the sampledelectrical signal conforms to predefined signal characteristics maycomprise, for example, a relative relation of the sampled electricalsignal to a predefined signal. In some embodiments, the sampledelectrical signal that is determined by the detection control circuit4100 to conform to the predefined signal characteristics may correspondto a determination or state that the LED tube lamp 1200 iscorrectly/properly connected to the lamp socket or there is nounintended external impedance being coupled to the LED tube lamp 1200,and the sampled electrical signal that is determined by the detectioncontrol circuit 4100 to not conform to the predefined signalcharacteristics may correspond to a determination or state where the LEDtube lamp 1200 is not correctly/properly connected to the lamp socket orthere is a foreign external impedance (e.g., a human body impedance,simulated/test human body impedance, or other impedance connected to thelamp and which the lamp is not designed to connect to for properlighting operations) being coupled to the LED tube lamp 1200.

In the steps S104 and S105, the first state and the second state canrefer to two distinct circuit-configuration states, and may be setaccording to the configured position and type of the current-limitingcircuit 4200. For example, in the case or embodiment where thecurrent-limiting circuit 4200 is independent of the driving circuit 530and refers to a switching circuit or a current-limiting circuit that isserially connected on the power loop, the first state is a conductingstate (or non-current-limiting state) while the second state is a cutoffstate (or current-limiting state).

Detailed operations and example circuit structures for performing theabove method in FIG. 44A as under the structure of FIG. 23 areillustrated by descriptions herein of different embodiments of aninstallation detection module.

FIG. 24A is a block diagram of an installation detection moduleaccording to some exemplary embodiments. Referring to FIG. 24A, theinstallation detection module 4000 a includes a detection pulsegenerating module 4110, a control circuit 4120, a detection determiningcircuit 4130, a switching circuit 4200 a, and a detection path circuit4160. The detection determining circuit 4130 is coupled to the detectionpath circuit 4160 through a path 4161, in order to detect a signal onthe detection path circuit 4160. The detection determining circuit 4130is also coupled to the control circuit 4120 through a path 4131, inorder to transmit a detection result signal to the control circuit 4120through the path 4131. The detection pulse generating module 4110 iscoupled to the detection path circuit 4160 through a path 4111 andgenerates a pulse signal to inform the detection path circuit 4160 of atime point to conduct a detection path or perform the installationdetection. The control circuit 4120 stores or latches a detection resultaccording to the detection result signal and is coupled to the switchingcircuit 4200 a through a path 4121, in order to transmit or reflect thedetection result to the switching circuit 4200 a. The switching circuit4200 a determines whether to conduct the current path between theinstallation detection terminals TE1 and TE2 (i.e., part of the powerloop). The detection path circuit 4160 is coupled to the power loop ofthe power supply module through a first detection connection terminalDE1 and a second detection connection terminal DE2. Detaileddescriptions related to the detection pulse generating module 4110,control circuit 4120, detection determining circuit 4130, and switchingcircuit 4200 a are similar to those of the embodiment of FIG. 19A, andthus are not repeated here again.

In the present embodiment, the detection path circuit 4160 has the firstdetection connection terminal DE1, the second detection connectionterminal DE2, and a third detection connection terminal DE3, in whichthe first detection connection terminal DE1 and second detectionconnection terminal DE2 are electrically connected to two inputterminals of a rectifying circuit 510 respectively to receive or samplean external driving signal through a first pin 501 and a second pin 502.The detection path circuit 4160 is configured to rectify thereceived/sampled external driving signal and to determine under thecontrol of the detection pulse generating module 4110 whether to conductthe rectified external driving signal through a detection path. Forexample, the detection path circuit 4160 is configured to determinewhether to conduct the detection path, in response to the control of thedetection pulse generating module 4110. Detailed circuit operations suchas using a pulse signal for conducting the detection path and detectingwhether there is any external impedance being connected to a conductivepart of the LED tube lamp are similar to those described in theembodiments of FIGS. 19B-19E, and thus are not repeatedly described hereagain.

In some embodiments, the installation detection module 4000 a furtherincludes an emergency control module 4140 and a ballast detection module4400, wherein operations of these two modules are similar to thosedescribed in the embodiment of FIG. 19A. A main difference of theembodiment of FIG. 24A from some previous embodiments is that theemergency control module 4140 and a ballast detection module 4400 of theembodiment of FIG. 24A are configured to determine and perform lateroperations by detecting the signal(s) at the input side/terminal of arectifying circuit 510, with the other structural and operationalsimilarities to the previous embodiments not described again.

FIG. 24B is a schematic circuit diagram of an installation detectionmodule according to some exemplary embodiments. Configurations andoperations of a detection path circuit 4160 of the present embodiment isdifferent from those in above embodiments of installation detectionmodule (as of FIGS. 19A-19C). A main difference is that the detectionpath circuit 4160 of FIG. 24B has current-limiting elements D91 and D92,which are for example, and hereinafter referred to as, a diode D91connected between a first rectifying input terminal (or the first pin501) and a first end of a resistor R91, and a diode D92 connectedbetween a second rectifying input terminal (or the second pin 502) andthe first end of the resistor R91, respectively. The diode D91 has ananode coupled to the first rectifying input terminal or a terminal ofthe rectifying circuit 510 connected to the first pin 501, and has acathode coupled to the first end of the resistor R91. The diode D92 hasan anode coupled to the second rectifying input terminal or a terminalof the rectifying circuit 510 connected to the second pin 502, and has acathode coupled to the first end of the resistor R91. In this embodimentof FIG. 30B, an external driving signal or AC signal received by thefirst and second pins 501 and 502 are provided to the first end of theresistor R91 via the diodes D91 and D92. During the positive half cycleof the external driving signal, the diode D91 is turned on as beingforward-biased and the diode D92 is turned off as being reverse-biased,making the detection path circuit 4160 equivalently form a detectionpath between the first rectifying input terminal (or pin 501) and asecond rectifying output terminal 512, which in this embodiment of FIG.24B is coupled to a second filtering output terminal 522 (through theswitching circuit 4200 a). During the negative half cycle of theexternal driving signal, the diode D91 is turned off as beingreverse-biased and the diode D92 is turned on as being forward-biased,making the detection path circuit 4160 equivalently form a detectionpath between the second rectifying input terminal (or pin 502) and thesecond rectifying output terminal 512.

The diodes D91 and D92 of the present embodiment serve to limit thedirection of the input AC signal, so that the first end of the resistorR91 receives a positive voltage (compared to the ground level) duringboth the positive half cycle and the negative half cycle of the input ACsignal, and therefore the phase change of the input AC signal, which mayaffect the voltage on the node X to cause a wrong detection result, isunlikely to affect the voltage on the node X when the diodes D91 and D92are included. Further, compared to some above embodiments, instead offorming a detection path directly connected on the power loop of thepower supply module, such as the detection path illustrated in FIGS. 19Bto 19D, the detection path circuit 4160 forms a detection path between(either of) the two rectifying input terminals and the second rectifyingoutput terminal 512 (or the ground terminal) through the diodes D91 andD92, which the detection path is separate from or substantiallyindependent from the power loop. Since the detection path circuit 4160is not directly connected to the power loop and only turned on under adetection mode, the current on the power loop for driving the LED modulewould not flow through the detection path circuit 4160 when the LED tubelamp is correctly/properly installed in the lamp socket and its powersupply module is operating normally. Therefore, since the detection pathcircuit 4160 does not need to withstand high current when the LED tubelamp's power supply module is operating normally, there is higherflexibility in selecting specifications of the components of thedetection path circuit 4160, and accordingly the power consumption onthe detection path circuit 4160 can be lower due to the flexibleselecting. Compared to the embodiments illustrated in FIGS. 19B to 19Dwhere a detection path is directly connected to the power loop, sincethe detection path circuit 4160 of FIG. 24B is not directly connected tothe filtering circuit 520 in the power loop, the issue of reversedischarging from a filtering capacitor of the filtering circuit 520 canbe avoided, which makes the circuit design simpler.

FIG. 25 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments. Referring to FIG. 25,the LED tube lamp 1300 is, for example, configured to receive anexternal driving signal directly provided by an external AC power source508, wherein the external driving signal is input through the live wire(marked as “L”) and the neutral wire (marked as “N”) to two pins 501 and502 on two ends of the LED tube lamp 1300. In practical applications,the LED tube lamp 1300 may further have two additional pins 503 and 504,also on the two ends. Under the structure of the LED tube lamp 1300having the four pins 501-504, depending on design needs two pins (suchas the pins 501 and 503, or the pins 502 and 504) on an end cap coupledto one end of the LED tube lamp 1300 may be electrically connected ormutually electrically independent, but the invention is not limited toany of the mentioned cases. A shock detection module 5000 is disposedinside the LED tube lamp 1300 and includes a detection control circuit5100 and a current-limiting circuit 5200. The shock detection module5000 may be and is hereinafter referred to as an installation detectionmodule 5000. The current-limiting circuit 5200 may be disposed incombination with a driving circuit 530, and may be the driving circuit530 itself or may comprise a bias adjustment circuit (to be furtherdescribed in embodiments below) configured for controlling theenabling/disabling of the driving circuit 530. From another perspective,a driving circuit 530 and a shock detection module 5000 as in FIG. 25may together be regarded or integrated as a driving circuit having thefunction of electric-shock detection or installation detection. Thedetection control circuit 5100 is electrically connected to a power loopof the LED tube lamp 1300 through a first detection connection terminalDE1 and a second detection connection terminal DE2, in order to sampleand detect, under a detection mode, a signal on the power loop, and isconfigured to control the current-limiting circuit 5200 according to thedetection result, so as to determine whether to prevent a current frompassing through the LED tube lamp 1300. When the LED tube lamp 1300 isnot yet correctly/properly installed into a lamp socket, the detectioncontrol circuit 5100 detects a relatively small current signal and thenassumes/presumes it to be facing or passing through relatively highimpedance, so the current-limiting circuit 5200 in response disables thedriving circuit 530 to prevent the LED tube lamp 1300 from operating ina normal lighting mode (i.e., suspending the LED tube lamp 1300 fromlighting up). On the other hand, when a relatively large current signalis detected or a relatively small current signal is not detected, thedetection control circuit 5100 determines that the LED tube lamp 1300 iscorrectly/properly installed into a lamp socket, and then thecurrent-limiting circuit 5200 allows the LED tube lamp 1300 to operatein a normal lighting mode (i.e., allowing the LED tube lamp 1300 beinglighted up) by enabling the driving circuit 530. In some embodiments,when a current signal on the power loop sampled and detected by thedetection control circuit 5100 is equal to or higher than a defined orset current value, the detection control circuit 5100 determines thatthe LED tube lamp 1300 is correctly/properly installed into a lampsocket and then causes the current-limiting circuit 5200 to enable thedriving circuit 530. But when the current signal sampled and detected bythe detection control circuit 5100 is lower than a defined or setcurrent value, the detection control circuit 5100 determines that theLED tube lamp 1300 is not correctly/properly installed into a lampsocket and thus causes the current-limiting circuit 5200 to disable thedriving circuit 530, thereby causing the LED tube lamp 1300 to enterinto a non-conducting state or limiting an effective current value on apower loop in the LED tube lamp 1300 to being smaller than, for example,5 mA (or 5MIU according to certain certification standards). Theinstallation detection module 5000 can be regarded as determiningwhether to cause current conduction or cutoff of the current-limitingcircuit 5200 based on the detected impedance, thereby causing the LEDtube lamp 1300 to operate in a conducting or normally driven state orenter into a current-limited state or non-driven state. Accordingly, anLED tube lamp 1300 using such an installation detection module 5000 hasthe benefit of avoiding or reducing the risk of electric shock hazardoccurring on the body of a user when accidentally touching or holding aconducting part of the LED tube lamp 1300 which is not yetcorrectly/properly installed into a lamp socket.

Specifically, when (part of) a human body touches or contacts the LEDtube lamp, impedance of the human body may cause a change in equivalentimpedance on a power loop in the LED tube lamp, so the installationdetection module 5000 of FIG. 25 can determine whether a human body hastouched or contacted the LED tube lamp by e.g. detecting a change incurrent/voltage on the power loop, in order to implement the function ofelectric-shock prevention. The installation detection module 5000 of thepresent embodiment can determine whether the LED tube lamp 1300 iscorrectly/properly installed into a lamp socket or whether the body of auser has accidentally touched a conducting part of the LED tube lampwhich is not yet correctly/properly installed into a lamp socket, bydetecting an electrical signal such as a voltage or current. Further,compared to the embodiments of FIGS. 14 and 23, since the currentlimiting function is implemented by controlling the driving circuit 530,an additional switching circuit, which may be designed for withstandinglarge current, serially connected on the power loop for providingelectric shock protection is not required. The sizes of selectedtransistor(s) in such a switching circuit are often strictly limited, sowhen such a switching circuit is omitted or not required, the overallcost of manufacturing the installation detection module 5000 can besignificantly reduced. From circuit operation perspectives, a methodperformed by the detection control circuit 5100 and configured todetermine under a detection mode whether the LED tube lamp 1300 iscorrectly/properly installed to a lamp socket or whether there is anyunintended external impedance being connected to the LED tube lamp 1300is shown in FIG. 44A. The method includes the following steps:temporarily conducting a detection path for a period and then cutting itoff (step S101); sampling an electrical signal on the detection pathduring the conduction period (step S102); determining whether the sampleof electrical signal conforms with predefined signal characteristics(step S103); if the determination result in step S103 is positive,controlling the current-limiting circuit 5200 to operate in a firststate (step S104); and if the determination result in step S103 isnegative, controlling the current-limiting circuit 5200 to operate in asecond state (step S105) and then returning to the step S101.

In the method of FIG. 44A performed in the embodiment of FIG. 25, thedetection path may be a current path connected to the output side of therectifying circuit 510, and its detailed circuit configurations in theembodiment are presented and illustrated below with reference to FIGS.26A to 30B. And detailed description of how to set parameters such asthe conduction period, intervals between multiple conduction periods,and the time point to trigger conduction, of the detection path in thedetection control circuit 5100 is also presented below for differentembodiments.

In the step S101, conducting the detection path for a period may beimplemented by means using pulse signal to control switching of aswitch.

In the step S102, the sample of electrical signal is a signal that canrepresent or express impedance variation on the detection path, whichsignal may comprise a voltage signal, a current signal, a frequencysignal, a phase signal, etc.

In the step S103, the operation of determining whether the sampledelectrical signal conforms to predefined signal characteristics maycomprise, for example, a relative relation of the sampled electricalsignal to a predefined signal. In some embodiments, the sampledelectrical signal that is determined by the detection control circuit5100 to conform with the predefined signal characteristics maycorrespond to a determination or state that the LED tube lamp 1300 iscorrectly/properly connected to the lamp socket or there is nounintended external impedance being coupled to the LED tube lamp 1300,and the sampled electrical signal that is determined to not conform bythe detection control circuit 5100 to the predefined signalcharacteristics may correspond to a determination or state where the LEDtube lamp 1300 is not correctly/properly connected to the lamp socket orthere is a foreign external impedance (e.g., a human body impedance,simulated/test human body impedance, or other impedance connected to thelamp and which the lamp is not designed to connect to for properlighting operations) being coupled to the LED tube lamp 1300.

In the steps S104 and S105 performed in the embodiment of FIG. 29, thefirst state and the second state are two distinct circuit-configurationstates, and may be set according to the configured position and type ofthe current-limiting circuit 5200. For example, in the case orembodiment where the current-limiting circuit 5200 refers to a biasadjustment circuit connected to a power supply terminal or enableterminal of a controller of the driving circuit 530, the first state isa cutoff state (or normal bias state, which allows the driving voltageto be normally supplied to the driving controller) while the secondstate is a conducting state (or bias adjustment state, which suspendsthe driving voltage from being supplied to the driving controller). Andin the case or embodiment where the current-limiting circuit 5200 refersto a power switch in the driving circuit 530, the first state is adriving-control state, where switching of the current-limiting circuit5200 is only controlled by the driving controller in the driving circuit530 and not affected by the detection control circuit 5100; while thesecond state is a cutoff state.

Detailed operations and example circuit structures for performing theabove method in FIG. 44A as under the structure of FIG. 25 areillustrated by descriptions herein of different embodiments of aninstallation detection module.

Referring to FIG. 25 again, in some embodiments, an LED tube lamp 5000further includes a flicker suppression circuit 590, which may be coupledto an LED module and, when the LED tube lamp 5000 is in a normaloperation mode, may be configured to adjust a current to be provided tothe LED module based on an input power line voltage signal, in order tocause a current flowing through the LED module to be smooth or even andto be unlikely to be affected by ripple voltages.

In some embodiments, the current-limiting circuit 5200 may be disposedin combination with the flicker suppression circuit 590; for example,the current-limiting circuit 5200 may be for example (part or all of)the flicker suppression circuit 590 itself, or may be a bias adjustmentcircuit for controlling enabling and/or disabling of the flickersuppression circuit 590, which will be further explained below inconnection with certain embodiments.

Although the same functional block is used to illustrate a drivingcircuit 530 and a flicker suppression circuit 590 in embodiments of FIG.25, they are not limited to being combined together. In actual practice,a driving circuit 530 and a flicker suppression circuit 590 may coexistor be present in a power supply module of an LED tube lamp.

Specifically, the detection control circuit 5100 of FIG. 25 iselectrically connected to a power loop of the LED tube lamp 1300 througha first detection connection terminal DE1 and a second detectionconnection terminal DE2, in order to sample and detect, under adetection mode, a signal on the power loop, and is configured to controlthe current-limiting circuit 5200 according to the detection result, soas to determine whether to prevent a current from passing through theLED tube lamp 1300. When the LED tube lamp 1300 is not yetcorrectly/properly installed into a lamp socket, the detection controlcircuit 5100 detects a relatively small current signal and thenassumes/presumes it to be facing or passing through relatively highimpedance, so the current-limiting circuit 5200 in response disables theflicker suppression circuit 590 in order to prevent the LED tube lamp1300 from operating in a normal operation mode or lighting up. On theother hand, when a relatively large current signal is detected or arelatively small current signal is not detected, the detection controlcircuit 5100 judges that the LED tube lamp 1300 is correctly/properlyinstalled into a lamp socket, and then the current-limiting circuit 5200enables the flicker suppression circuit 590 in order to cause the LEDtube lamp 1300 to operate in a normal operation mode, wherein the LEDtube lamp 1300 may light up and the enabled flicker suppression circuit590 adjusts a current flowing through an LED module based on variationin a voltage signal. In some embodiments, when a current signal on thepower loop sampled and detected by the detection control circuit 5100 isequal to or higher than a defined or set current value, the detectioncontrol circuit 5100 judges that the LED tube lamp 1300 iscorrectly/properly installed into a lamp socket and then causes thecurrent-limiting circuit 5200 to enable the flicker suppression circuit590 to suppress variation in current in response to ripple voltages onthe power line voltage signal, in order to suppress the flicker problemin the LED tube lamp. But when the current signal sampled and detectedby the detection control circuit 5100 is lower than a defined or setcurrent value, the detection control circuit 5100 judges that the LEDtube lamp 1300 is not correctly/properly installed into a lamp socketand thus causes the current-limiting circuit 5200 to disable the flickersuppression circuit 590, thereby causing the LED tube lamp 1300 to enterinto a non-conducting state or limiting an effective current value on apower loop in the LED tube lamp 1300 to being smaller than for example 5mA or 5 MIU according to certain standards.

FIG. 26A is a block diagram of an installation detection moduleaccording to an exemplary embodiment. Referring to FIG. 26A, theinstallation detection module 5000 a includes a detection pulsegenerating module 5110 (which may be referred to a first circuit 5110),a control circuit 5120 (which may be referred to a third circuit 3480),a detection determining circuit 5130 (which may be referred to a secondcircuit 5130), and a detection path circuit 5160 (which may be referredto a fourth circuit 5160). The detection pulse generating module 5110 iselectrically connected to the detection path circuit 5160 via a path5111 and is configured to generate a control signal having at least onepulse. The detection path circuit 5160 is electrically connected to thepower loop of the power supply module via a first detection connectionterminal DE1 and a second detection connection terminal DE2 and isconfigured to turn on a detection path during pulse-on period of thecontrol signal. The detection determining circuit 5130 is electricallyconnected to the detection path via a path 5161, and is configured todetermine an installation state between the LED tube lamp and the lampsocket according to a signal feature on the detection path. A detectionresult signal corresponding to the determination result is generated andtransmitted to the control circuit 5120 via a path 5131. The controlcircuit 5120 is electrically connected to the driving circuit 530 via apath 5121 and is configured to affect or adjust the bias of the drivingcircuit to control the operating state of the driving circuit 530, inwhich the driving circuit 530 itself or the power switch of the drivingcircuit 530 can be regarded as a current-limiting circuit 5200 a. Insuch a case, the control circuit 5120 may act or be regarded as thedriving controller of the driving circuit 530.

Based on the aspects of the operation of the installation detectionmodule 5000 a, when the LED tube lamp is powered up, the detection pulsegenerating module 5110 is enabled in response to the connected powersource and generates pulse to temporarily turn-on or conduct thedetection path formed by the detection path circuit 5160. During theperiod of the detection path being turned on, the detection determiningcircuit 5130 samples signal on the detection path to determine whetherthe LED tube lamp is correctly installed in the lamp socket or whether aleakage current is generated by touching the conductive part of the LEDtube lamp. The detection determining circuit 5130 generates acorresponding detection result signal, according to the determinationresult, and transmits it to the control circuit 5120. When the controlcircuit 5120 receives the detection result signal indicating the LEDtube lamp has been correctly installed in the lamp socket, the controlcircuit 5120 transmits a corresponding installation state signal tocontrol the driving circuit 530 to normally perform power conversion forproviding electricity to the LED module. On the contrary, when thecontrol circuit 5120 receives the detection result signal indicating theLED tube lamp is not correctly installed in the lamp socket, the controlcircuit 5120 transmits a corresponding installation state signal tocontrol the driving circuit 530 to stop its normal operation or to bedisabled. Since the driving circuit 530 disables, the current flowingthrough the power loop can be limited to less than a safety value (e.g.,5 MIU).

The configuration and operation of the detection pulse generating module5110, the detection determining circuit 5130 and the detection pathcircuit 5160 can be seen referring to the description of relevantembodiments of the present disclosure. The difference between theembodiment illustrated in FIG. 26A and the other relevant embodiments isthat the control circuit 5120 can be configured for controlling theoperation of the driving circuit 530 in the back end, so that thedriving circuit 530 can be disabled by adjusting the bias voltage whenthe LED tube lamp is not correctly installed or when the risk ofelectric shock exists. Under such configuration, the switch circuit(e.g., switch circuit 3200, 3200 a-L), which is disposed on the powerloop and thus required to withstand high current, can be omitted, andtherefore the cost of the overall installation detection module can besignificantly reduced. On the other hand, since the leakage current islimited by controlling the bias voltage of the driving circuit 530through the control circuit 5120, the circuit design of the drivingcircuit 530 does not need to be changed, so as to make thecommercialization easier.

In an exemplary embodiment, the detection pulse generating module 5110,detection path circuit 5160, detection determining circuit 5130, andcontrol circuit 5120 can be respectively implemented by, but not limitedto, the circuit configurations illustrated in FIGS. 26B to 26F. Detailedoperations of each of the module and circuits are described below withreference to FIGS. 26B to 26F.

FIG. 26B is a schematic circuit diagram of the detection pulsegenerating module according to some embodiments. Referring to FIG. 26B,the detection pulse generating module 5110 includes resistors Ra1 andRa2, a capacitor Cal and a pulse generating circuit 5112. The resistorRa1 has a first end and a second end, wherein the first end of theresistor Ra1 is electrically connected to the rectifying circuit 510 viathe rectifying output terminal 511. The resistor Ra2 has a first endelectrically connected to the second end of the resistor Ra1 and asecond end electrically connected to the rectifying circuit 510 via therectifying output terminal 512. The capacitor Cal is connected to theresistor Ra2 in parallel. The pulse generating circuit 5112 has an inputterminal connected to a connection terminal of the resistors Ra2 and Caland an output terminal connected to the detection path circuit 5160 andfor outputting a control signal having pulse DP.

In some embodiments, the resistors Ra1 and Ra2 form a voltage divisionresistor string configured to sample a bus voltage (i.e., the voltage onthe power line of the power supply module). The pulse generating circuit5112 determines a time point for generating the pulse DP according tothe bus voltage and outputs the pulse DP as the control signal Sc basedon a pulse-width setting. For example, the pulse generating circuit 5112may output the pulse DP after the bus voltage rises or falls acrosszero-voltage point for a period, so that the issue of misjudgment causedby performing installation detection on the zero-voltage point can beaddressed. The characteristics of the pulse waveform and the pulseinterval setting can be seen by referring to the description of relevantembodiments, and thus are not repeated herein.

FIG. 26C is a schematic circuit diagram of the detection path circuitaccording to some embodiments. Referring to FIG. 26C, the detection pathcircuit 5160 includes a resistor Ra3, a transistor Ma1 and a diode Dal.The resistor Ra3 has a first end connected to the rectifying outputterminal 511. The transistor Ma1 is, for example, a MOSFET or a BJT, andhas a first terminal connected to a second end of the resistor Ra3, asecond terminal connected to the rectifying output terminal 512, and acontrol terminal receiving the control signal Sc. The diode Dal has ananode connected to the first end of the resistor Ra3 and the rectifyingoutput terminal 511 and a cathode connected to the input terminal of thefiltering circuit in the back end. Taking a pi-filter as an example, thecathode of the diode Dal can be regarded as electrically connected tothe connection terminal of the capacitor 725 and the inductor 726.

In the embodiment illustrated in FIG. 26C, the resistor Ra3 and thetransistor Ma1 form a detection path, which can be conducted when thetransistor Ma1 is turned on by the control signal Sc. During the periodof the detection path being conducted, the detection voltage Vdetchanges due to current flowing through the detection path, and theamount of the voltage changes is determined according to the equivalentimpedance of the detection path. Taking the detection voltage Vdet,which samples from the first end of the resistor Ra3, as shown in FIG.26C as an example, during the period of the detection path beingconducted, the detection voltage Vdet substantially equals the busvoltage on the rectifying output terminal 511 if there is no bodyimpedance being electrically connected (e.g., if the LED tube lamp iscorrectly installed); and if there is a body impedance electricallyconnected between the rectifying output terminal 511 and the groundterminal, the detection voltage Vdet changes into a voltage division ofthe resistor and the body impedance. Accordingly, the detection voltageVdet can indicate whether a body impedance is electrically connected tothe LED tube lamp.

FIG. 26D is a schematic circuit diagram of the detection determiningcircuit according to some embodiments. Referring to FIG. 26D, thedetection determining circuit 5130 includes a sampling circuit 5132, acomparison circuit 5133 and a determining circuit 5134. According tosome embodiments, the sampling circuit 5133 may sample the detectionvoltage Vdet according to a set time point and generate a plurality ofsample signals Ssp_t1 to Ssp_tn, respectively corresponding to thedetection voltage Vdet at different time points. The comparison circuit5133 is electrically connected to the sampling circuit 5132 and receivesthe sample signals Ssp_t1 to Ssp_tn. In some embodiments, part or all ofthe sample signals Ssp_t1 to Ssp_tn are selected to be compared witheach other by the comparison circuit 5133 to generate a comparisonresult Scp. In some embodiments, the comparison circuit 5133 calculatesa difference between any two of the sample signals Ssp_t1 to Ssp_tn andthen compares the difference with a preset signal. In some embodiments,the comparison circuit 5133 compares the sample signals Ssp_t1 to Ssp_tnwith a preset signal to generate a comparison result Scp. In someembodiments, the comparison circuit 5133 compares two sample signals atadjacent time points to generate a corresponding comparison result Scp.The comparison result Scp will be outputted to the determining circuit5134 after being generated.

Specifically, when the LED tube lamp is correctly installed into a lampsocket (or when there is no touching/connecting external impedance), thefirst detection connection terminal DE1 (as the first rectifying outputterminal 511) and second detection connection terminal DE2 (as thesecond rectifying output terminal 512) of the detection path circuit5160 are equivalently directly connected to the external power source,so no matter whether the detection path of the detection path circuit5160 is conducted or not, the voltage waveform of the detected voltageVdet varies along with the phase change in the external driving signaland thus is in a complete waveform of a sinusoidal signal. Therefore,when the LED tube lamp is correctly installed into a lamp socket, nomatter whether the detection path of the detection path circuit 5160 isconducted or not, the sampling circuit 5132 may generate the pluralityof sample signals Ssp_t1 to Ssp_tn having the same voltage level orclose voltage levels respectively.

On the other hand, when the LED tube lamp is not correctly installedinto a lamp socket, or when there is touching/connecting externalimpedance (e.g., body impedance), the first detection connectionterminal DE1 is equivalent to electrically connect, through the externalimpedance, to the external power source. During a time when thedetection path is being conducted, the detected voltage Vdet is droppeddue to voltage division between the external impedance and the impedanceon the detection path (such as resistor Ra3), so as to cause thewaveform of the detected voltage Vdet to present discontinuous ornon-smooth variations or changes in voltage levels, which means thevoltage level has abruptly changed while the detection path is beingconducted. During a time when the detection path is not being conducted,since at this time there is typically no conducting current path in thepower loop of the LED tube lamp, there is almost and ideally no voltagedrop at the first detection connection terminal DE1, and thus thewaveform of the detected voltage Vdet maintains its normal completesinusoidal form. As a result, an installation detection module maydetermine whether there is an external body impedance touching the LEDtube lamp, by identifying the difference in characteristics betweenvoltage waveforms of the detected voltage Vdet. The following is adescription of several exemplary mechanisms of this determining.

Refer to FIGS. 26D and 26E, where FIG. 26E is a signal waveform diagramof an installation detection module according to some embodiments. Inthe present embodiment, the sampling circuit 5132 may sample thedetected voltage Vdet at the same phase point during each period of thedetected voltage Vdet, in order to sample at least one signal level(such as the sample signal Ssp_t1) at the same phase point in one periodof the detected voltage Vdet and during a pulse period DPW and sample atleast one signal level (such as the sample signal Ssp_t2) at the samephase point in another period of the detected voltage Vdet and outside apulse period DPW. When the LED tube lamp is not correctly installed intoa lamp socket, a signal level sampled by the sampling circuit 5132during the pulse period DPW (e.g., the sample signal Ssp_t1) is lowerthan that sampled by the sampling circuit 5132 outside of each pulseperiod DPW (e.g., the sample signals Ssp_t2). As a result, thecomparison result Scp corresponding to the installation state can begenerated by selecting and comparing part or all of the sample signalsSsp_t1 to Ssp_tn, by comparing part or all of the sample signals Ssp_t1to Ssp_tn with a defined signal, or by comparing a signal, obtained bycalculating a difference between two of the sample signals Ssp_t1 toSsp_tn, with a defined signal. For example, the comparison circuit 5133may generate a comparison result Scp with a first logic level when thevoltage levels of the sample signals Ssp_t1 and Ssp_t2 are the same orvery close, and may generate a comparison result Scp with a second logiclevel when the difference between the voltage levels of the samplesignals Ssp_t1 and Ssp_t2 reaches a set value. The comparison result Scpwith the first logic level refers to the condition in which the LED tubelamp is correctly installed into a lamp socket, while the comparisonresult Scp with the second logic level refers to the condition in whichthe LED tube lamp is not correctly installed into a lamp socket.

The determining circuit 5134 receives the comparison result Scp andoutputs a detection result signal Sdr. In some embodiments, thedetermining circuit 5134 can be configured to output the detectionresult signal Sdr indicating correct installation after (continuously ordiscontinuously) receiving a certain number of positive comparisonresults Scp, wherein the positive comparison result Scp refers to thecomparison result Scp meeting the requirement of a correct installationcondition, for example, the level of the sample signal is higher thanthe preset signal.

Referring to both FIGS. 26D and 26F, where FIG. 26F is a signal waveformdiagram of an installation detection module (as 5000 a) according tosome embodiments. In the present embodiment, when the LED tube lamp iscorrectly installed into a lamp socket, the voltage level of thedetected voltage Vdet during each pulse period DPW is approximatelysmoothly changing from that of the detected voltage Vdet at the startingpoint and ending point of the pulse period DPW, which smooth changing isillustrated by the broken line along the detected voltage signal Vdetduring the pulse period DPW. On the contrary, when the LED tube lamp isnot correctly installed into a lamp socket, the voltage level of thedetected voltage Vdet during each pulse period DPW is significantlylower than that of the detected voltage Vdet at the starting point andending point of the pulse period DPW, and thus is not smoothly changingfrom that of the detected voltage Vdet at the starting point and endingpoint of the pulse period DPW, which non-smooth changing is illustratedby the solid line along the detected voltage signal Vdet during thepulse period DPW. Therefore, the sampling circuit 5132 may be configuredto sample the detected voltage Vdet at least one time close to andeither before the starting point or after the ending point of a pulsesignal DP1, and configured to sample the detected voltage Vdet at leastone time during the pulse signal DP1, so that during one period of thedetected voltage Vdet at least one signal level (such as the samplesignal Ssp_t1) outside a pulse period DPW is sampled and at least onesignal level (such as the sample signal Ssp_t2) during the pulse periodDPW is sampled.

The case of the sampling circuit 5132 sampling the detected voltage Vdetbefore the starting point of a pulse signal DP1 is taken as an example.When the LED tube lamp is correctly installed into a lamp socket, thesampling circuit 5132 samples to get a signal voltage level Vt1(corresponding to the sample signal Ssp_t1) at a time point t1 beforeentering into a pulse period DPW, which signal voltage level Vt1 islower than a signal voltage level Vt3 (corresponding to the samplesignal Ssp_t2) obtained by sampling at a time point t2 during the pulseperiod DPW. On the contrary, when the LED tube lamp is not correctlyinstalled into a lamp socket, the sampling circuit 5132 samples to get asignal voltage level Vt1 (corresponding to the sample signal Ssp_t1) ata time point t1 before entering into a pulse period DPW, which signalvoltage level Vt1 is higher than a signal voltage level Vt2(corresponding to the sample signal Ssp_t2) obtained by sampling at atime point t2 during the pulse period DPW.

The comparison circuit 5133 may be configured to generate a comparisonresult Scp corresponding to an installation state by comparing thesample signal Ssp_t2 and the sample signal Ssp_t1, comparing each of thesample signal Ssp_t2 and the sample signal Ssp_t1 with a set value, orcomparing a difference between the sample signal Ssp_t2 and the samplesignal Ssp_t1 with a set value.

Operations of comparing the sample signals Ssp_t1 and Ssp_t2 are takenas an example. For this case, the comparison circuit 5133 may beconfigured to generate a comparison result Scp of a first logic levelwhen the signal voltage level (such as Vt3) of the sample signal Ssp_t2is greater than or equal to the signal voltage level (such as Vt1) ofthe sample signal Ssp_t1; and configured to generate a comparison resultScp of a second logic level when the signal voltage level (such as Vt2)of the sample signal Ssp_t2 is smaller than the signal voltage level(such as Vt1) of the sample signal Ssp_t1.

Operations of comparing each of the sample signals Ssp_t1 and Ssp_t2with a set value are taken as an example. For this case, the set valuemay be designed to be, for example but it's not limited to, a valuebetween such signal voltage levels Vt1 and Vt3. In some embodiments, thecomparison circuit 5133 may be configured to generate a comparisonresult Scp of a first logic level when the signal voltage level (such asVt3) of the sample signal Ssp_t2 is greater than the set value and thesignal voltage level (such as Vt1) of the sample signal Ssp_t1 issmaller than the set value; and configured to generate a comparisonresult Scp of a second logic level when each of the signal voltage level(such as Vt2) of the sample signal Ssp_t2 and the signal voltage level(such as Vt1) of the sample signal Ssp_t1 is smaller than the set value.

Operations of comparing the difference between the sample signals Ssp_t1and Ssp_t2 with a set value are taken as an example. For this case, theset value may be designed to be, for example, a value between (Vt2-Vt1)and (Vt3-Vt1). Specifically, if the signal voltage level Vt1 is 20V, thesignal voltage level Vt2 is 12V, and the signal voltage level Vt3 is25V, then the set value may be designed to be between −8V (=Vt2-Vt1) and5V (=Vt3-Vt1). In some embodiments, the set value may be designed to be0V. Also for this case, the comparison circuit 5133 may be configured togenerate a comparison result Scp of a first logic level when thedifference (such as Vt3-Vt1) in signal voltage level between the samplesignals Ssp_t2 and Ssp_t1 is greater than or equal to the set value; andconfigured to generate a comparison result Scp of a second logic levelwhen the difference (such as Vt2-Vt1) in signal voltage level betweenthe sample signals Ssp_t2 and Ssp_t1 is smaller than the set value. Sucha difference as described for this case may be calculated by one ofdifferent methods according to different circuit designs of relevantstructures related to the comparison circuit 5133, and is for examplecalculated by a voltage level sampled later minus a voltage levelsampled earlier, calculated by a voltage level sampled earlier minus avoltage level sampled later, or calculated by taking the absolute valueof the difference between two sampled voltage levels (or a greatersampled voltage level minus a smaller sampled voltage level), and thepresent invention is not limited to any of these ways of calculation.

In each of the above three cases of comparing operations, a comparisonresult Scp of a first logic level indicates conforming to the conditionthat the LED tube lamp is correctly installed into a lamp socket, whilea comparison result Scp of a second logic level indicates conforming tothe condition that the LED tube lamp is not correctly installed into alamp socket.

It should be noted that the described sampling of the detected voltageVdet and ways of comparing by the comparison circuit 5133 are not onlyapplicable to the installation detection module (as 5000 a) in theembodiment of FIG. 26A, but also applicable to an installation detectionmodule in other embodiments, including especially an embodiment wherethere is a detection path circuit such as described herein.

In some embodiments, the above described circuit operations may beperformed or realized by the steps of the flowchart in FIG. 44E, whichinclude receiving a detection voltage signal (such as Vdet) on adetection path circuit (such as 5160) (step S501); sampling thedetection voltage signal during a conduction state of the detection pathcircuit (such as during a pulse period DPW of a pulse signal), togenerate a first sample signal (step S502); sampling the detectionvoltage signal during a cutoff state of the detection path circuit (suchas under the control of a pulse signal), to generate a second samplesignal (step S503); and judging whether the LED tube lamp meets acorrect-installation condition according to the voltage levels of thefirst sample signal and the second sample signal (step S504).

As illustrated by the signal waveforms of FIG. 26E, the step S502 maycomprise sampling a detection voltage signal Vdet at a time point t1 togenerate a first sample signal Ssp_t1 during a pulse period DPW, and thestep S503 may comprise sampling the detection voltage signal Vdet at atime point t2 to generate a second sample signal Ssp_t2 outside a pulseperiod DPW. In practice, the step S502 and the step S503 may for examplebe performed by using a pulse signal DP1/DP2 to trigger a samplingcircuit 5132 to perform a first-time signal sampling followed byperforming signal sampling later at constant intervals for two times,wherein the constant interval may be designed to have a length of one oran integer multiple of a half signal period of a power supply signalfrom an AC power grid, such as a length in the range of between 10 ms(corresponding to a half signal period of a 50 Hz signal) and 16.67 ms(corresponding to a half signal period of a 60 Hz signal), but thepresent invention is not limited to any of these two lengths.

As illustrated by the signal waveforms of FIG. 26F, the step S502 maycomprise sampling a detection voltage signal Vdet at a time point t2 togenerate a first sample signal Ssp_t2 during a pulse period DPW, and thestep S503 may comprise sampling the detection voltage signal Vdet at atime point t1 to generate a second sample signal Ssp_t1 outside a pulseperiod DPW. From these two ways of performing the steps S502 and S503 asillustrated by FIGS. 26E and 26F, it is understood that according to thedistinct adopted detection structure or plan, the order or sequence ofperforming the steps S502 and S503 of FIG. 44E may be interchanged,which means in some embodiments the step S502 is performed beforeperforming the step S503, but in some other embodiments the step S503 isperformed before performing the step S502.

FIG. 26G is a circuit diagram illustrating a control circuit of aninstallation detection module according to some embodiments. Referringto FIG. 26F, the control circuit 5120 has an input terminal configuredto receive a detection result signal Sdr and an output terminalelectrically connected to a controller 633 of a driving circuit 630,which driving circuit 630 may have configurations similar to those of adescribed embodiment herein of FIG. 16B. So the driving circuit 630'sconfigurations are not repeatedly described.

When the control circuit 5120 receives a detection result signal Sdrindicating correct installation state (the external impedance does notconnect to the LED tube lamp), the control circuit 5120 transmits acorresponding installation state signal Sidm to the controller 633 ofthe driving circuit 630, which controller 633 is then enabled oractivated in response to the installation state signal Sidm and controlsthe operation of a switch 635 so as to generate a driving signal todrive an LED module. On the other hand, when the control circuit 5120receives a detection result signal Sdr indicating incorrect/improperinstallation state (the external impedance connects to the LED tubelamp), the control circuit 5120 transmits a corresponding installationstate signal Sidm to the controller 633 of the driving circuit 630,which controller 633 is then disabled or not activated, in response tothe installation state signal Sidm.

In some embodiments, the controller 633 and the control circuit 5120 ofFIG. 26G may be integrated together, wherein the controller 633 and thecontrol circuit 5120 as a whole may be regarded as a driving controllerfor the driving circuit 630 of FIG. 26G.

Here an exemplary embodiment is described with reference to FIG. 26Hwhich illustrates a circuit diagram of the detection circuit and thedriving circuit according to one embodiment. The detection circuit ofthe present embodiment is similar to the embodiments of FIGS. 26B to 26Fand includes a detection pulse generating module 5110, a control circuit5120, a detection determining circuit 5130, and a detection path circuit5160. The driving circuit 1030 takes the power conversion circuitstructure in FIG. 9B for example and includes a controller 1033, a diode1034, a transistor 1035, an inductor 1036, a capacitor 1037, and aresistor 1038.

Compared to the embodiments of FIGS. 26B to 26G, the detection pathcircuit 5160 is for example in a configuration similar to that of adetection path circuit 3660 in FIG. 20B, and includes a transistor Ma1and a resistor Ra1. The drain terminal of the transistor Ma1 isconnected to the common end of the capacitors 725 and 727, and thesource terminal of the transistor Ma1 is connected to a first end of theresistor Ra1. The second end of the resistor Ra1 is coupled to the firstground terminal GND1. And it is noted that the first ground terminalGND1 and the second ground terminal GND2 of the LED module 50 may be thesame ground terminal or two electrically independent ground terminals,while the present invention is not limited to any one of these options.

The detection pulse generating module 5110 is coupled to the gateterminal of the transistor, and is used to control conduction state ofthe transistor Ma1. The detection determining circuit 5130 is coupled toa first end of the resistor Ra1 and the controller 1033, and isconfigured to sample an electrical signal on the first end of theresistor Ra1 and then compare the sampled electrical signal with areference signal, so as to determine whether the LED tube lamp iscorrectly installed. The detection determining circuit 5130 generatesand transmits an installation detection signal Sidm to the controller1033 according to the comparison result. In this embodiment, operationdetails and characteristics about the detection pulse generating module5110, the control circuit 5120, the detection determining circuit 5130,and the detection path circuit 5160 can be similar to those about thedetection pulse generating module 3610, the detection path circuit 3660,and the detection determining circuit 3630 of FIG. 20B and thus are notrepeatedly described here.

In summary, regarding the power supply module described above, theinstallation detection function and the electric shock protectionfunction are integrated into the driving circuit, so that the drivingcircuit becomes the driving circuit having the installation detectionfunction and the electric shock protection function. Specifically, forthe circuit structure in one embodiment, only an additional detectioncircuit, for detecting the electrical signal on the power loop/detectionpath, is used to implement the installation detection function and theelectric shock protection function with the driving circuit 1030. Forexample, through adjusting a control method in the driving circuit 1030,the detection pulse generating module, the detection result latchingcircuit, the detection determining circuit and the switch circuit of theinstallation detection module 3000 can be implemented by the hardwarecircuit structure of an existing driving circuit 1030, without requiringadditional circuit elements. Since the detection pulse generatingmodule, the detection result latching circuit, the detection determiningcircuit and the switch circuit are not required, the cost of the overallpower supply module can be effectively reduced. In addition, since thecircuit components/elements are reduced, the power supply module mayhave more area for layout and the power consumption can be reduced. Thesaved power can be used for driving the LED module so as to enhance theluminous efficiency, and the heat caused by the power supply module canbe reduced as well.

Configuration and operation method of the detection circuit in theexemplary embodiment of FIG. 26H can be similar to the detection pulsegenerating module, the detection path circuit, and the detectiondetermining circuit of the installation detection module 3000, and thedetection result latching circuit and the switch circuit of theinstallation detection module 3000 are replaced in the exemplaryembodiment of FIG. 26H by existing controller and power switch of thedriving circuit 1030. In the exemplary embodiment of FIG. 26C, through aspecific configuration of the detection path circuit 5160, the format ofthe installation detection signal Sidm can easily be designed to becompatible with signal format of the controller 1033, so that circuitdesign difficult can be significantly reduced on the basis of a reducedcircuit complexity.

It's noted that although the embodiment of FIG. 26H is described andillustrated to include the configuration of the detection path circuit3660 in FIG. 20B, the present invention is not limited to thisconfiguration of FIG. 20B. In other applications, the detection pathcircuit may be configured as in the above other embodiments described,to implement the transient sampling or detection of the electricalsignal.

In some embodiments, the installation detection module 5000 a shown inFIG. 26A may selectively include a dimming circuit 5170 for realizing adimming function (or adjusting of brightness of a lighting LED module)of an LED tube lamp. As shown in FIG. 26A, the dimming circuit 5170 iselectrically connected to a first detection connection terminal DE1through a path 5171, and electrically connected to the control circuit5120 through a path 5172. In a normal operation mode, the dimmingcircuit 5170 may be configured to generate a dimming signal based on areceived electrical signal, and to provide the dimming signal to thecontrol circuit 5120 through the path 5172. Then based on the receiveddimming signal the control circuit 5120 is configured to adjustcontrolling of a power switch, in order to adjust the luminance of alighting LED module corresponding to the dimming signal. Though thedimming circuit 5170 is illustrated in FIG. 26A as being directlyconnected to a first detection connection terminal DE1 for receiving anelectrical signal, the present invention is not limited to such aconnection.

Specifically, in the process of operations for normally lighting up anLED tube lamp, the dimming circuit 5170 may be configured to sample anelectrical signal on a power loop to obtain a dimming message therein,wherein the dimming message may originate from a message which wasconverted or changed into a corresponding signal feature according to aspecific way or specified rule and carried into an input power signalfor the LED tube lamp, i.e. the input power signal is a carrier signal.A way for the dimming circuit 5170 to obtain the dimming message may beby performing reverse conversion on or demodulating the signal featureobtained by the sampling. Based on the obtained dimming message, thedimming circuit 5170 may further generate a dimming signal conforming tothe input-voltage rating of the control circuit 5120, which may be thena driving controller for a driving circuit 530, for causing the controlcircuit 5120 to perform dimming control according to the generateddimming signal.

Upon an LED tube lamp starting to receive electrical power and thenperforming electric-shock detection (as in a detection mode), since theLED tube lamp is not yet lighted up, there is no need yet to perform adimming function, so in some embodiments during the detection mode thedimming circuit 5170 is maintained in a disabled state, and the dimmingcircuit 5170 is only enabled, which may be realized by an enablingsignal issued by the control circuit 5120, after confirming that thedetection is finished, in order to avoid misoperation or wrong operationof the control circuit 5120 due to influence of the dimming signal.

In some embodiments, a dimming circuit 5170 is electrically connected toan input terminal of a rectifying circuit (such as 510), for obtaining adimming message by sampling a not yet rectified external driving signal.

In some embodiments, a dimming circuit 5170 is configured to receive adimming control signal through an independent or separate port orinterface, and to generate a dimming signal corresponding to thereceived dimming control signal.

In some embodiments, the detection pulse generating module 5110, controlcircuit 5120, detection determining circuit 5130, and dimming circuit5170 of FIG. 26A may be integrated together into a unit to act as adriving controller for the driving circuit 530 in order to controloperation of a power switch, for the power supply module to have theintegrated functions of constant-current driving, electric-shockdetection, and dimming control. The following description furtherexplains a whole circuit structure and configurations of a power supplymodule having the integrated functions of constant-current driving,electric-shock detection, and dimming control with reference to FIG.26I. FIG. 26I is a schematic diagram of a power supply module having thefunctions of constant-current driving, electric-shock detection, anddimming control according to some embodiments. Referring to FIG. 26I,the power supply module of such an embodiment includes a rectifyingcircuit 510, a filtering circuit 520, a driving circuit 1530, and adetection path circuit 5160. Configurations and operations of thepassive components 1534, 1536, and 1537 in the rectifying circuit 510,filtering circuit 520, and driving circuit 1530 are similar or analogousto those of such components in other embodiments described above. A maindifference between the embodiment of FIG. 26I and the embodimentspreviously described is that the driving circuit 1530 of the embodimentof FIG. 26I includes a multi-function or multi-function drivingcontroller 533 m having the integrated functions of constant-currentdriving, electric-shock detection, and dimming control. Themulti-function driving controller 533 m may include a control circuit5120 m and a power switch 1535, wherein the control circuit 5120 m undera detection mode is configured to cause periodically brief conduction ofthe detection path circuit 5160 in order to judge the installation stateof the LED tube lamp. Upon judging that the LED tube lamp is correctlyinstalled into a lamp socket the control circuit 5120 m is configured toenter into a normal operation mode to issue a lighting control signalfor controlling switching of the power switch 1535, in order for thedriving circuit 1530 to generate a stable current for driving an LEDmodule 50. Furthermore, in the normal operation mode, the controlcircuit 5120 m may be configured to obtain a dimming message accordingto a sample electrical signal from the detection path circuit 5160, andconfigured to adjust the lighting control signal based on the obtaineddimming message, in order to adjust the luminance of the LED module 50accordingly. For example, when obtaining a dimming message indicating a50% of luminance, the control circuit 5120 m may be configured to adjustthe duty cycle of the power switch 1535 to be half of its rated value,which rated duty-cycle value corresponds to 100% of the rated luminance,in order to reduce the effective value of an output current of thedriving circuit 1530, thereby reducing the luminance of the LED module50 to be half of its rated luminance.

In some embodiments, if the sampling point of the detection path circuit5160 is directly connected to the first detection connection terminalDE1, the control circuit 5120 m may be regarded as sampling anelectrical signal directly from the first detection connection terminalDE1 or the power loop.

In some embodiments, the detection path circuit 5160 and themulti-function driving controller 533 m may be integrated together andas a whole be regarded as a driving controller for the driving circuit1530.

FIG. 27A is a block diagram of an installation detection moduleaccording to some embodiments. Referring to FIG. 27A, the installationdetection module 5000A includes a detection pulse generating module5110, a detection determining circuit 5130, a detection path circuit5160, and a current-limiting circuit 5200A. Configurations andoperations of the detection pulse generating module 5110, detectiondetermining circuit 5130, and detection path circuit 5160 are similar tothose of the above analogous embodiments of FIGS. 26A-26E, and thus arenot repeatedly described here.

A difference between the embodiment illustrated in FIG. 27A and theother analogous embodiments is that the current-limiting circuit 5200Aof FIG. 27A comprises or is implemented by a bias adjustment circuit5200A. The detection determining circuit 5130 is configured to transmita detection result signal Sdr to the bias adjustment circuit 5200A,which is coupled to a driving circuit 530 through a path 5201 and isconfigured to affect or adjust the bias voltage of the driving circuit530 in order to control the operation state of the driving circuit 530.

FIG. 27B is a schematic circuit diagram of the control circuit accordingto some embodiments. Referring to FIG. 27B, the bias adjustment circuit5200A includes a transistor Ma2, which has a first terminal electricallyconnected to the connection terminal of a resistor Rbias and a capacitorCbias and the power input terminal of the controller 633, a secondterminal electrically connected to the second filtering output terminal522, and a control terminal for receiving the adjustment control signalVctl. In some embodiments, the resistor Rbias and the capacitor Cbiascan be regarded as an external bias circuit of the driving circuit 630,which is configured to provide an operating power for the controller633.

When the detection determining circuit 5130 determines that the LED tubelamp has been correctly installed in the lamp socket (no body impedanceintroduced), the detection determining circuit 5130 outputs a disablingdetection result signal Sdr to the transistor Ma2, and the transistorMa2 cuts off in response to the disabling detection result signal Sdr.Under such state, the bias voltage can be provided to the controller 633and thus enables the controller 633 to control the switching of theswitch, and the lamp driving signal can be therefore generated to drivethe LED module.

When the detection determining circuit 5130 determines that the LED tubelamp is not correctly installed in the LED tube lamp (body impedanceintroduced), the detection determining circuit 5130 outputs an enablingdetection result signal Sdr to the transistor Ma2 to turn the transistorMa2 on, so as to electrically connect the power input terminal of thecontroller 633 to the ground terminal. Under such a state, thecontroller 633 disables due to the power input terminal being grounded.It worth noting that an additional leakage path may be formed throughthe transistor Ma2 when the transistor Ma2 is turned on, however, theleakage current does not harm the human body, and meets the safetyrequirement since the bias voltage applied to the controller 633 isrelatively low.

FIG. 28A is a block diagram of an installation detection module 5000 bfor an LED tube lamp according to some embodiments. Referring to FIG.28A, the installation detection module 5000 b includes a detection pulsegenerating module 5110, a control circuit 5120, a detection determiningcircuit 5130, and a detection path circuit 5160. Configurations andoperations of the detection pulse generating module 5110, detection pathcircuit 5160, and detection determining circuit 5130 are similar tothose of the above described embodiments of FIGS. 26A-26E, and thus arenot repeatedly described here.

A main difference of the embodiment of FIG. 28A from some previousembodiments is that a current-limiting circuit 5200 b is disposed with aflicker suppression circuit 590 in the embodiments of FIG. 28A. Inoperation, a detection result signal Sdr from the detection determiningcircuit 5130 is transmitted to the control circuit 5120, in order tocontrol operation of the flicker suppression circuit 590 through thecontrol circuit 5120. The control circuit 5120 is connected to theflicker suppression circuit 590 through a path 5121, and in a detectionmode is configured to control operation state of the flicker suppressioncircuit 590. In a normal operation mode, the flicker suppression circuit590 is configured to perform current adjustment or compensationaccording to a detected voltage, in order to reduce the amplitude of adriving current output by a driving circuit, thereby suppressing rippleor flicker phenomena.

Compared to the embodiments of FIG. 14 or 23, since the current-limitingcircuit 5200 b of the embodiments of FIG. 28A achieves thefunction/effects of current limiting or electric-shock protection bycontrolling a flicker suppression circuit 590, it's not needed toadditionally and serially connect a switching circuit on a power loop ofthe LED tube lamp for electric-shock protection, so the overall cost inmanufacturing an installation detection module without such a switchingcircuit is significantly lower.

FIG. 28B is a circuit diagram illustrating a control circuit 5120 of aninstallation detection module (as 5000 a) according to some embodiments.Referring to FIG. 28B, a flicker suppression circuit 690 of theseembodiments includes a voltage generating circuit 691, an operationalamplifier 692, a resistor 693, and a transistor 694. The voltagegenerating circuit 691 is coupled to a control circuit 5120, in order togenerate a reference voltage Vref. The operational amplifier 692 has twoinput terminals and one output terminal, wherein one (such as a positiveinput terminal) of the two input terminals is coupled to an outputterminal of the voltage generating circuit 691 in order to receive thereference voltage Vref, and the other (such as a negative inputterminal) of the two input terminals is coupled to the resistor 693 andthe transistor 694. The resistor 693 has a first end coupled to theoperational amplifier 692 and transistor 694, and has a second endcoupled to a second driving output terminal or a ground terminal. Andthe transistor 694 has a first terminal coupled to a cathode or negativeterminal of the LED module 50, a second terminal coupled to theoperational amplifier 692 and the first end of the resistor 693, and acontrol terminal coupled to the output terminal of the operationalamplifier 692.

Specifically, referring to FIGS. 28A and 28B, when the detectiondetermining circuit 5130 judges that the LED tube lamp is not correctlyinstalled into a lamp socket or is still in a detection mode, thecontrol circuit 5120 based on a received detection result signal Sdrindicating incorrect-installation state is configured to transmit acorresponding installation state signal Sidm to the voltage generatingcircuit 691, which then adjusts the reference voltage Vref to a groundvoltage level or low level in response to the installation state signalSidm, to cause the operational amplifier 692 to output a disablingsignal or not output any signal, in order to cause or maintain thetransistor 694 in a cutoff state. On the other hand, when the detectiondetermining circuit 5130 judges that the LED tube lamp is correctlyinstalled into a lamp socket or is in a normal operation mode, thecontrol circuit 5120 based on a received detection result signal Sdrindicating correct-installation state is configured to transmit acorresponding installation state signal Sidm to the voltage generatingcircuit 691, which then adjusts the reference voltage Vref to a properstable value, enabling the operational amplifier 692 based on the properreference voltage Vref and a voltage detected from the resistor 693 togenerate a control signal to control operation of the transistor 694within a linear region.

For example, referring to FIGS. 28A and 28B, under a normal operationmode, when the power line voltage increases, the voltage Vd at thenegative input terminal of the operational amplifier 692 also increases,to cause the difference between the reference voltage Vref and thevoltage Vd to decrease. Then the operational amplifier 692 is configuredto generate a lower-voltage level control signal to drive the transistor694, causing an equivalent impedance between the first and secondterminals of the transistor 694 to be relatively large. On the contrary,when the power line voltage decreases, the voltage Vd at the negativeinput terminal of the operational amplifier 692 also decreases, to causethe difference between the reference voltage Vref and the voltage Vd toincrease. Then the operational amplifier 692 is configured to generate ahigher-voltage level control signal to drive the transistor 694, causingan equivalent impedance between the first and second terminals of thetransistor 694 to be relatively small. Accordingly, when the power linevoltage increases, the LED module 50 is in effect serially connected toincreasing or higher impedance, but when the power line voltagedecreases, the equivalent impedance connected in series with the LEDmodule 50 decreases in response, so that no matter how the power linevoltage varies the magnitude of current flowing through the LED module50 can be maintained at a stable or nearly constant value, therebyavoiding/reducing the incidence of flicker phenomenon.

FIG. 29A is a block diagram of an installation detection module 5000Bfor an LED tube lamp according to some embodiments. Referring to FIG.29A, the installation detection module 5000B includes a detection pulsegenerating module 5110, a detection determining circuit 5130, adetection path circuit 5160, and a current-limiting circuit 5200B.Configurations and operations of the detection pulse generating module5110, detection path circuit 5160, and detection determining circuit5130 of FIG. 29A are similar to those of the above described embodimentsof FIGS. 26A-26E, and thus are not repeatedly described here.

A main difference of the embodiment of FIG. 29A from some previousembodiments is that the current-limiting circuit 5200B of the embodimentof FIG. 29A comprises or is implemented by a bias adjustment circuit5200B. The detection determining circuit 5130 is configured to transmita detection result signal Sdr to the bias adjustment circuit 5200B,which is coupled to a flicker suppression circuit 590 through a path5121 and is configured to affect or adjust the bias voltage of theflicker suppression circuit 590 in order to control operation state ofthe flicker suppression circuit 590.

FIG. 29B is a circuit diagram of a bias adjustment circuit 5200Baccording to some embodiments. Referring to FIG. 29B, the biasadjustment circuit 5200B includes a transistor Mb1. The transistor Mb1has a first terminal electrically connected to a common node between aresistor Rbias and a capacitor Cbias and an enabling terminal of aflicker suppression circuit 690 (or a voltage generating circuit 691); asecond terminal electrically connected to a second driving outputterminal 532; and a control terminal for receiving a detection resultsignal Sdr. In this embodiment of FIG. 29B, the resistor Rbias andcapacitor Cbias act as an external biasing circuit for the flickersuppression circuit 690 and configured to provide power for the flickersuppression circuit 690 (or the voltage generating circuit 691) tooperate.

Specifically, referring to FIGS. 29A and 29B, when the detectiondetermining circuit 5130 judges that the LED tube lamp is not correctlyinstalled into a lamp socket or is still in a detection mode, thedetection determining circuit 5130 is configured to transmit an enablingdetection result signal Sdr to the transistor Mb1, which then conductsin response to the enabling detection result signal Sdr, causing theenabling terminal of the flicker suppression circuit 690 to be in effectshorted to ground (through the second driving output terminal 532),which prevents the voltage generating circuit 691 from being activated.At this state, the reference voltage Vref in FIG. 29B is maintained at aground voltage level or low level, causing the operational amplifier 692of FIG. 29B to output a disabling signal or not to output any signal,maintaining the transistor 694 of FIG. 29B in a cutoff state. On theother hand, when the detection determining circuit 5130 judges that theLED tube lamp is correctly installed into a lamp socket or is in anormal operation or lighting mode, the detection determining circuit5130 is configured to transmit a disabling detection result signal Sdrto the transistor Mb1, which then is cut off in response to thedisabling detection result signal Sdr, and therefore the flickersuppression circuit 690 or the voltage generating circuit 691 cannormally generate a reference voltage Vref, enabling the operationalamplifier 692 based on the generated reference voltage Vref and avoltage Vd detected from the resistor 693 of FIG. 29B to generate acontrol signal to control operation of the transistor 694 within alinear region.

For example, referring to FIGS. 29A and 29B, under a normal operationmode, when the power line voltage increases, the voltage Vd at thenegative input terminal of the operational amplifier 692 increases inresponse, to cause the difference between the reference voltage Vref andthe voltage Vd to decrease. Then the operational amplifier 692 isconfigured to generate a lower-voltage level control signal to drive thetransistor 694, causing an equivalent impedance between the first andsecond terminals of the transistor 694 to be relatively large. On thecontrary, when the power line voltage decreases, the voltage Vd at thenegative input terminal of the operational amplifier 692 decreases inresponse, to cause the difference between the reference voltage Vref andthe voltage Vd to increase. Then the operational amplifier 692 isconfigured to generate a higher-voltage level control signal to drivethe transistor 694, causing an equivalent impedance between the firstand second terminals of the transistor 694 to be relatively small.Accordingly, when the power line voltage increases, the LED module 50 isin effect serially connected to increasing or higher impedance, but whenthe power line voltage decreases, the equivalent impedance connected inseries with the LED module 50 decreases in response, so that no matterhow the power line voltage varies the magnitude of current flowingthrough the LED module 50 can be maintained at a stable or nearlyconstant value, thereby avoiding/reducing the incidence of flickerphenomenon.

FIG. 29C is a circuit diagram of a bias adjustment circuit 5200Baccording to some embodiments. Referring to FIG. 29C, the biasadjustment circuit 5200B includes a transistor Mb2. The transistor Mb2has a first terminal connected to an enabling terminal of an operationalamplifier 692 (which is the terminal connected to a biasing voltageVdd); a second terminal connected to a second driving output terminal532; and a control terminal for receiving a detection result signal Sdr.The embodiment of FIG. 29C is largely similar to the embodiments of FIG.29B, with a main difference that the bias adjustment circuit 5200B ofthe embodiment of FIG. 29C achieves enabling/disabling of a flickersuppression circuit 690 of FIG. 29C by controlling whether the enablingterminal of the operational amplifier 692 is grounded or not.

Specifically, referring to FIGS. 29A and 29C, when the detectiondetermining circuit 5130 judges that the LED tube lamp is not correctlyinstalled into a lamp socket or is still in a detection mode, thedetection determining circuit 5130 is configured to transmit an enablingdetection result signal Sdr to the transistor Mb2, which then conductsin response to the enabling detection result signal Sdr, causing theenabling terminal of the operational amplifier 692 to be in effectshorted to ground (through the second driving output terminal 532). Atthis state, no matter what the voltage Vd on the resistor 693 is, theoperational amplifier 692 outputs a disabling signal or is regarded asnot outputting an enabling signal, to maintain the transistor 694 in acutoff state. On the other hand, when the detection determining circuit5130 judges that the LED tube lamp is correctly installed into a lampsocket or is in a normal operation or lighting mode, the detectiondetermining circuit 5130 is configured to transmit a disabling detectionresult signal Sdr to the transistor Mb2, which then is cut off inresponse to the disabling detection result signal Sdr, and therefore theoperational amplifier 692 can normally receive the biasing voltage Vdd,enabling the operational amplifier 692 based on the reference voltageVref and a voltage Vd detected from the resistor 693 of FIG. 29C togenerate a control signal to control operation of the transistor 694within a linear region. Other related operations in the embodiment ofFIG. 29C are similar to those described above in the embodiments ofFIGS. 29A and 29B, so are not described again here.

FIG. 30A is a block diagram of an installation detection moduleaccording to some exemplary embodiments. Referring to FIG. 30A, the LEDtube lamp includes a rectifying circuit 510, a filtering circuit 520 anda driving circuit 1130. Compared with the embodiment of FIG. 5A, the LEDtube lamp of the present embodiment further includes a detection circuit5000 b. The connection between the rectifying circuit 510, the filteringcircuit 520, the driving circuit 1130 and the LED module 50 are similarto the embodiment illustrated in FIG. 5A, and thus is not described indetail herein. The detection circuit 5000 b has an input terminalcoupled to the power loop of the LED tube lamp and an output terminalcoupled to the driving circuit 1130.

Specifically, after the LED tube lamp is powered up (no matter whetheror not the LED tube lamp is correctly installed in the lamp socket), thedriving circuit 1130 enters an installation detection mode. Under theinstallation detection mode, the driving circuit 1130 provides alighting control signal having narrow pulse (e.g., the pulse-on periodis smaller than 1 ms) for driving the power switch (not shown), so thatthe driving current, generated under the installation detection mode, issmaller than 5 MIU or 5 mA. On the other hand, under the installationdetection mode, the detection circuit 5000 b detects an electricalsignal on the power loop/detection path and generates an installationdetection signal Sidm, in which the installation detection signal Sidmis transmitted to the driving circuit. The driving circuit 1130determines whether to enter a normal driving mode according to thereceived installation detection signal Sidm. If the driving circuit 1130determines to maintain in the installation detection mode, which meansthe LED tube lamp is not correctly installed in the lamp socket duringthe first pulse, the next pulse is output, according to a frequencysetting, for temporarily conducting the power loop/detection path, sothat the electrical signal on the power loop/detection path can bedetected by the detection circuit 5000 b again. On the contrary, if thedriving circuit 1130 determines to enter the normal driving mode, thedriving circuit 1130 generates, according to at least one of the inputvoltage, the output voltage, the input current, the output current andthe combination of the above, the lighting control signal capable ofmodulating the pulse width for maintaining the brightness of the LEDmodule 50. In the present embodiment, the input/output voltage and theinput/output current can be sampled by a feedback circuit (not shown) inthe driving circuit 1130.

FIG. 30B is a schematic diagram of an exemplary driving circuitaccording to some exemplary embodiments. Referring to FIG. 30B, thedriving circuit 1130 includes a controller 1133 and a conversion circuit1134. The controller 1133 includes a signal receiving unit 1137, asawtooth wave generating unit 1138 and a comparison unit CUd, and theconversion circuit 1134 includes a switch circuit (also known as powerswitch) 1135 and energy release circuit 1136. The signal receiving unit1137 has input terminals for receiving a feedback signal Vfb andinstallation detection signal Sidm and an output terminal coupled to afirst input terminal of the comparison unit CUd. The sawtooth wavegenerating unit 1138 has an output terminal coupled to a second inputterminal of the comparison unit CUd. An output terminal of thecomparison unit CUd is coupled to a control terminal of the switchcircuit 1135. The circuit arrangement of the switch circuit 1135 and theenergy release circuit 1136 can be referred to with respect to theembodiments of FIGS. 9A to 9E, and it will not be repeated herein.

In the controller 1133, the signal receiving unit 1137 can beimplemented by, for example, a circuit constituted by an erroramplifier. The error amplifier is configured to receive the feedbacksignal Vfb related to the voltage/current information of the powersupply module and the installation detection module Sidm. In the presentembodiment, the signal receiving unit 1137 selectively outputs a presetvoltage Vp or the feedback signal Vfb to the first input terminal of thecomparison unit CUd. The sawtooth wave generating unit 1138 isconfigured to generate and provide a sawtooth signal Ssw to the secondinput terminal of the comparison unit CUd. In the waveform of thesawtooth signal Ssw of each cycle, the slope of at least one of therising edge and the falling edge is not infinity. In some embodiments,the sawtooth wave generating unit 1138 generates the sawtooth signalSsw, according to a fixed operation frequency, no matter what theoperation mode of the driving circuit 1130 is. In some embodiments, thesawtooth wave generating unit 1138 generates the sawtooth signal Sswaccording to different operation frequencies when operating in differentoperation modes. For example, the sawtooth wave generating unit 1138 canchange the operation frequency according to the installation detectionsignal Sidm. The comparison unit CUd compares the signal level of thesignal on the first and the second input terminal, in which thecomparison unit CUd outputs the lighting control signal Slc with highvoltage level when the signal level on the first input terminal isgreater than the second input terminal and outputs the lighting controlsignal Slc with low voltage level when the signal level on the firstinput terminal is not greater than the second input terminal. Forexample, the comparison unit CUd outputs high voltage when the signallevel of the sawtooth signal Ssw is greater than the preset voltage Vpor the feedback signal Vfb, so as to generate the lighting controlsignal having pulse waveform.

FIG. 41C is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. Referring to FIGS. 30B and41C, when the LED tube lamp is powered up (including the pins on theboth end caps being connected to the connecting sockets, or the pins onone end cap being connected to the corresponding connecting socket andthe pins on the other end cap being touched by the user), the drivingcircuit 1130 starts to operate and enter the installation detection modeDTM. The operation in the first period T1 is described below. Under theinstallation detection mode, the signal receiving unit 1137 outputs thepreset voltage Vp to the first input terminal of the comparison unitCUd, and the sawtooth wave generating unit 1138 provides the sawtoothsignal SW to the second input terminal of the comparison unit CUd. Fromthe perspective of the variation of the sawtooth wave SW, the signallevel of the sawtooth wave SW gradually increases, after the starttimepoint ts, from the initial level to a peak level. After reaching thepeak level, the sawtooth wave SW is gradually decreased to the initiallevel. Before the signal level of the sawtooth wave SW rises to thepreset voltage Vp, the comparison unit CUd outputs the lighting controlsignal Slc with low voltage. During the period from the timepoint of thesignal level rising to exceed the preset voltage Vp to the timepointfalling back below the preset voltage Vp, the comparison unit CUd pullsthe signal level up to the high voltage. After the signal level fallingto lower than the preset voltage Vp, the comparison unit CUd pulls thesignal level down to the low voltage again. By performing the aboveoperation, the comparison unit CUd can generate the pulse DP based onthe sawtooth wave SW and the preset voltage Vp, in which the pulsewidth/pulse-on period DPW of the pulse DP is the duration that thesignal level of the sawtooth wave SW is higher than the preset voltageVp.

The lighting control signal Slc having the pulse DP is transmitted tothe control terminal of the switch circuit 1135, so that the switchcircuit 1135 is turned on during the pulse-on period DPW. Therefore, theenergy release unit 1136 absorbs power and a current is generated on thepower loop/detection path in response to the switch circuit being turnedon. Since the current generated on the power loop/detection path leadsto a signal feature, such as signal level, waveform, and/or frequencychanging, the signal feature variation of the sample signal Ssp will bedetected by the detection circuit 5000 b. In the present embodiment, thedetection circuit 5000 b detects the voltage for example, but theinvention is not limited thereto. Under the first period T1, since thevoltage variation SP does not exceed the reference voltage Vref, thedetection circuit 5000 b output the corresponding installation detectionsignal Sidm to the signal receiving unit 1137, so that the signalreceiving unit 1137 is maintained in the installation detection mode DTMand continuously outputs the preset voltage Vp to the comparison unit1137. Since the voltage variation of the sample signal Ssp under thesecond period T2 is similar to the sample signal Ssp under the firstperiod T1, the circuit operation under the first and the second periodsT1 and T2 are similar, so that the detailed description is not repeatedherein.

Conclusively, under the first and the second periods T1 and T2, the LEDtube lamp is determined to be not correctly installed. In addition,during the first and the second periods T1 and T2, although the drivingcircuit 1130 generates the driving current on the power loop, thecurrent value of the driving current does not cause electric shock tothe human body because of the turn-on time of the switch circuit 1135 isrelatively short, in which the current value is smaller than 5 MIU/mAand can be reduced to 0.

After entering the third period T3, the detection circuit 5000 bdetermines the voltage variation of the sample signal Ssp exceeds thereference voltage Vref, so as to provide the corresponding installationdetection signal Sidm, indicating the LED tube lamp is correctlyinstalled, to the signal receiving unit 1137. When the signal receivingunit 1137 receives the installation detection signal Sidm indicating thecorrect installation state, the driving circuit 1130 enters, after theend of the third period T3, the normal driving mode DRM from theinstallation detection mode DTM. Under the fourth period T4 of thenormal driving mode DRM, the signal receiving unit 1137 generates thecorresponding signal to the comparison unit CUd according to thefeedback signal Vfb instead of the preset voltage Vp, so that thecomparison unit CUd is capable of dynamically modulating the pulse-onperiod of the lighting control signal Slc according to the drivinginformation such as the input voltage, the output voltage and/or thedriving current. From the perspective of the signal waveform of thelighting control signal Sc, since the pulse DP is configured to detectthe installation state/risk of electric shock, the pulse width of thepulse DP is relatively narrow, compared to the pulse width under thenormal driving mode DRM. For example, the pulse width of the pulse underthe installation detection mode DTM (e.g., DP) is less than the minimumpulse width under the normal driving mode DRM.

In some embodiments, the detection circuit 5000 b stops operating underthe normal driving mode DRM. In some embodiments, under the normaldriving mode DRM, the signal receiving unit 1137 ignores theinstallation detection signal Sidm regardless of whether the detectioncircuit 5000 b continuously operates.

Referring to FIG. 30A again, in some exemplary embodiments, when the LEDtube lamp is powered up (no matter whether it's correctly installed ornot), the detection circuit 5000 b would be enabled based on forming ofa current path in the LED tube lamp, and the enabled detection circuit5000 b detects an electrical signal on a power loop in a short period oftime and then according to the detection result transmits aninstallation detection signal Sidm to the driving circuit 1130, whereinthe driving circuit 1130 determines whether to operate or be enabled toperform power conversion, according to the received installationdetection signal Sidm. Upon the detection circuit 5000 b transmitting aninstallation detection signal Sidm indicating the LED tube lamp iscorrectly installed, the driving circuit 1130 in response is enabled andthen generates a lighting control signal to drive a power switch, so asto convert received power to output power for the LED module. In thiscase, after transmitting the installation detection signal Sidmindicating the LED tube lamp is correctly installed, the detectioncircuit 5000 b would switch into an operation mode not affecting thepower conversion by the driving circuit 1130. On the other hand, uponthe detection circuit 5000 b transmitting an installation detectionsignal Sidm indicating the LED tube lamp is incorrectly installed, thedriving circuit 1130 in response remains disabled until receiving aninstallation detection signal Sidm indicating the LED tube lamp iscorrectly installed. In this case when the driving circuit 1130 remainsdisabled, the detection circuit 5000 b continues in the detection modefor detecting the electrical signal on the power loop until detectingthat the LED tube lamp is correctly installed.

In summary, compared to the power supply module described above, theinstallation detection function and the electric shock protectionfunction are integrated into the driving circuit, so that the drivingcircuit becomes a driving circuit having the installation detectionfunction and the electric shock protection function. Specifically, forthe circuit structure in one embodiment as illustrated in FIG. 30A, onlyan additional detection circuit (as 5000 b), for detecting theelectrical signal on the power loop/detection path, is needed toimplement the installation detection function and the electric shockprotection function with a driving circuit 1130. That is, througharranging a control logic in the driving circuit 1130, the function ofthe detection pulse generating module, the detection result latchingcircuit, the detection determining circuit, and the switching circuit ofthe installation detection module 5000 b can be implemented by theexisting hardware of the driving circuit 1030, without adding circuitelements. Since the complex circuit designs such as the detection pulsegenerating module, the detection result latching circuit, the detectiondetermining circuit, and the switching circuit of the installationdetection module are not required in the power supply module, the costof the overall power supply module can be effectively reduced. Further,since the circuit components/elements are reduced, the power supplymodule may have more area for layout and the power consumption can bereduced. The saved power can be used for driving the LED module so as toenhance the luminous efficiency, and the heat caused by the power supplymodule can be reduced as well.

FIG. 31A is a block diagram of an installation detection moduleaccording to some embodiments. Referring to FIG. 31A, the power supplymodule in this embodiment includes a rectifying circuit 510, a filteringcircuit 520, an installation detection module 5000 d, and a drivingcircuit 1230, wherein the rectifying circuit 510 and the filteringcircuit 520 are configured in a way similar to the above describedembodiments. The installation detection module 5000 d includes adetection triggering circuit which is disposed on the power loop of theLED tube lamp, for example after the stage of the filtering circuit 520as shown in FIG. 31A, but the present embodiment is not limited to thisposition of the detection triggering circuit 5000 d. The detectiontriggering circuit 5000 d is coupled to an input power terminal orvoltage detection terminal of the driving circuit 1230, whose outputterminal(s) is/are coupled to the LED module 50.

In this embodiment, the detection triggering circuit 5000 d is enabledwhen external power is applied to the power supply module of the LEDtube lamp, to transform an electrical signal at the output terminal ofthe filtering circuit 520 into an electrical signal of a first waveformto be provided to the input power terminal or voltage detection terminalof the driving circuit 1230. The driving circuit 1230 then enters into adetection mode when receiving the first-waveform electrical signal, inorder to output a narrow-width pulse signal, conforming to a specificdetection need, to drive the power switch; and the driving circuit 1230further determines whether the LED tube lamp is properly/correctlyinstalled in a lamp socket, by detecting the magnitude of currentflowing through the power switch or the LED module 50. Upon determiningthat the LED tube lamp is properly/correctly installed, the drivingcircuit 1230 will switch or enter into a normal operating mode (or LEDoperating mode) to drive the power switch, in which mode the drivingcircuit 1230 is able to provide stable output power to light up the LEDmodule 50. During this normal operating mode, the detection triggeringcircuit 5000 d is disabled so as not to affect power provided from thefiltering circuit 520 to the driving circuit 1230, and therefore theelectrical signal being provided to the input power terminal or voltagedetection terminal of the driving circuit 1230 is not of the firstwaveform. On the other hand, upon determining that the LED tube lamp isnot properly/correctly installed, the driving circuit 1230 willcontinually output the narrow-width pulse signal to drive the powerswitch.

The embodiment illustrated by FIG. 31A is further elaborated in detailhere taking the specific circuits in FIGS. 31B and 31C as examples ofthe circuit blocks in FIG. 31A. FIG. 31B is a circuit diagramillustrating the detection triggering circuit 5310 and the drivingcircuit 1230 according to some embodiments, and FIG. 31C is anapplication circuit diagram illustrating an integrated controller 1233of the driving circuit 1230 according to some embodiments. In thisembodiment of the driving circuit 1230, the driving circuit 1230includes the controller 1233, an inductor 1236, a diode 1234, acapacitor 1237, and a resistor 1238, wherein the integrated controller1233 has several signal receiving terminals, such as a power supplyterminal P_VIN, a voltage detection terminal P_VSEN, a current detectionterminal P_ISEN, a driving terminal P_DRN, a compensation terminalP_COMP, and a reference ground P_GND. An end of the inductor 1236 andthe anode of the diode 1234 are connected to the driving terminal P_DRNof the controller 1233. The resistor 1238 is connected to the currentdetection terminal P_ISEN of the controller 1233. The detectiontriggering circuit 5310 in this embodiment may comprise for example aswitch circuit, which is connected to the voltage detection terminalP_VSEN of the controller 1233. In addition, for meeting operation needsof the integrated controller 1233, the power supply module of the LEDtube lamp may further include one or more auxiliary circuits external tothe integrated controller 1233, such as resistors Rc1 and Rc2 connectedto output terminals of the filtering circuit 520. Other externalauxiliary circuits not illustrated in FIG. 31B may be included in thepower supply module.

The integrated controller 1233 includes a pulse control unit PCU, apower switch unit PSW, a current control unit CCU, a gain amplificationunit Gm, a bias unit BU, a detection triggering unit DTU, a switchingunit SWU, and comparison units CU1 and CU2. The pulse control unit PCUis configured to generate a pulse signal to control the power switchunit PSW. The power switch unit PSW is connected to the inductor 1236and the diode 1234 through the driving terminal P_DRN, and is configuredto switch on or off in response to the control by the pulse signal,enabling the inductor 1236 to alternately store and release power undernormal operating mode in order to provide a stable output current to theLED module 50. The current control unit CCU receives a voltage detectionsignal VSEN through the voltage detection terminal P_VSEN, and throughthe current detection terminal P_ISEN receives a current detectionsignal I_(SEN) indicating the magnitude of current flowing through theresistor 1238. Therefore the current control unit CCU under the normaloperating mode can learn about the real-time operating state of the LEDmodule 50 according to the voltage detection signal VSEN and the currentdetection signal I_(SEN), and then generate an output regulation signalaccording to the real-time operating state of the LED module 50. Theoutput regulation signal is processed by the gain amplification unit Gmand thereby provided to the pulse control unit PCU as a reference signalfor the pulse control unit PCU to generate the pulse signal. The biasunit BU is configured to receive a filtered signal output by thefiltering circuit 520, and then generate both stable driving voltage VCCand reference voltage V_(REF) to be used by the units in the integratedcontroller 1233. The detection triggering unit DTU is connected to thedetection triggering circuit 5310 and the resistors Rc1 and Rc2 throughthe voltage detection terminal P_VSEN, and is configured to detectwhether characteristics of the voltage detection signal VSEN receivedthrough the voltage detection terminal P_VSEN conform to that of thefirst waveform. The detection triggering unit DTU then according to thedetection result outputs a detection result signal to the pulse controlunit PCU. The switching unit SWU is connected to a first end of theresistor 1238 through the current detection terminal P_ISEN, and isconfigured to provide the current detection signal I_(SEN) selectivelyto the comparison unit CU1 or the comparison unit CU2, according to thedetection result of the detection triggering unit DTU. The comparisonunit CU1 is mainly used for overcurrent protection, and is configured tocompare the received current detection signal I_(SEN) with anovercurrent reference signal V_(OCP) and then output a comparison resultto the pulse control unit PCU. And the comparison unit CU2 is mainlyused for electric shock protection, and is configured to compare thereceived current detection signal I_(SEN) with an installation referencesignal V_(IDM) and then output a comparison result to the pulse controlunit PCU.

Specifically, when the LED tube lamp is powered up, the detectiontriggering circuit 5310 would first be enabled and would then affect oradjust, by for example switching of a switch, the voltage detectionsignal VSEN (to be) provided at the voltage detection terminal P_VSEN,so as to make the voltage detection signal VSEN have the first waveform.For example, taking a switch as the detection triggering circuit 5310,upon being enabled the detection triggering circuit 5310 may in a shortperiod continually switch for several times between a conduction stateand a cutoff state on predefined intervals, to cause the voltagedetection signal VSEN to vary/fluctuate in a voltage waveform reflectingthe switching of the detection triggering circuit 5310. The defaultstate of the integrated controller 1233 upon initially receivingelectrical power is disabled. For example, during this state the pulsecontrol unit PCU does not output the pulse signal to drive the powerswitch unit PSW to light up the LED module 50. But during this state ofthe integrated controller 1233 the detection triggering unit DTUdetermines whether the voltage detection signal VSEN has(characteristics of) the first waveform and then transmits thedetermination result to the pulse control unit PCU.

When the pulse control unit PCU receives from the detection triggeringunit DTU a signal indicating that the voltage detection signal VSENconforms with (characteristics of) the first waveform, the integratedcontroller 1233 enters into an installation detection mode. Under theinstallation detection mode, the pulse control unit PCU outputs anarrow-width pulse signal to drive the power switch unit PSW, limiting acurrent flowing through the power loop of the LED tube lamp to beingbelow a level (such as 5MIU) over which level there will be substantialrisk of electric shock on a human body. Detailed configuration of thepulse signal under the installation detection mode is similar to and canbe set with reference to that in the above described embodiments of theinstallation detection module. In one respect, under the installationdetection mode, the switching unit SWU switches into a circuitconfiguration for transmitting the current detection signal I_(SEN) tothe comparison unit CU2, such that the comparison unit CU2 compares thereceived current detection signal I_(SEN) with the installationreference signal V_(IDM) and generates a comparison result. In thisconfiguration of the switching unit SWU, when the LED tube lamp isimproperly/incorrectly installed, the second end of the resistor 1238can be regarded as connected to the ground terminal GND1 via the bodyimpedance Rbody. Since the intervening of the body impedance Rbody maycause the equivalent impedance increases, the body impedance Rbody canbe reflected in variation of the current detection signal I_(SEN), andthus the pulse control unit PCU can correctly determine, according tothe comparison result of the comparison unit CU2, whether the LED tubelamp is properly/correctly installed to a lamp socket or whether therisk of electric shock may occurred. Thus if the pulse control unit PCUdetermines that the LED tube lamp is improperly/incorrectly installed toa lamp socket according to the comparison result of the comparison unitCU2, then the integrated controller 1233 remains operating in theinstallation detection mode, for example, the pulse control unit PCUcontinues to output a narrow-width pulse signal to drive the powerswitch unit PSW and judges whether the LED tube lamp isproperly/correctly installed to a lamp socket according to the currentdetection signal I_(SEN). But if the pulse control unit PCU determinesthat the LED tube lamp is properly/correctly installed to a lamp socketaccording to the comparison result, the integrated controller 1233 thenenters into a normal operating mode.

Under the normal operating mode, the detection triggering circuit 5000 dis inactive or disabled, for example, the detection triggering circuit5000 d doesn't affect or adjust the voltage detection signal VSEN. Inthis case, the voltage detection signal VSEN is determined merely byvoltage division between the resistors Rc1 and Rc2, and in theintegrated controller 1233 the detection triggering unit DTU may bedisabled or the pulse control unit PCU doesn't use the detection resultsignal from the detection triggering unit DTU. Also in this case, thepulse control unit PCU adjusts the pulse width of the pulse signalmainly according to signal(s) output by the current control unit CCU andthe gain amplification unit Gm, in a way to output a pulse signal havinga corresponding rated power to drive the power switch unit PSW, therebyproviding a stable output current to the LED module 50. In one respect,under the normal operating mode, the switching unit SWU switches into acircuit configuration for transmitting the current detection signalI_(SEN) to the comparison unit CU1, to enable the comparison unit CU1 tocompare the received current detection signal I_(SEN) with theovercurrent reference signal V_(OCP), so that the pulse control unit PCUcan adjust its output pulse signal during an overcurrent condition toprevent circuit damage. It should be noted that the overcurrentprotection function available in the integrated controller 1233 ismerely optional. In other embodiments, the comparison unit CU1 may beomitted, and the switching unit SWU is accordingly omitted, in theintegrated controller 1233, resulting in the current detection signalI_(SEN) being directly provided to an input terminal of the comparisonunit CU2.

FIG. 31D is a circuit diagram illustrating the detection triggeringcircuit 5000 d and the driving circuit 1330 according to someembodiments. The embodiment is similar to that in FIG. 31B, with a maindifference that the embodiment of FIG. 31B further includes aconfiguration of a transistor Mp and an array Rpa of parallel-connectedresistors, wherein the transistor Mp has a drain terminal connected tothe first end of the resistor 1338, a gate terminal connected to adetection control terminal of the integrated controller 1333, and asource terminal connected to a first common end of the resistor arrayRpa. The resistor array Rpa includes a plurality of parallel-connectedresistors, whose resistances can be set based on that of the resistor1338, and the second common end of the resistor array Rpa is connectedto the ground terminal GND1.

In some embodiments, the integrated controller 1333 outputs a signal viathe detection control terminal to the gate terminal of the transistor Mpaccording to its current operation mode, so that the transistor Mp canbe turned on in response to the received signal, or can be cut off orturned off in response to the received signal during the normaloperating mode. In the case of where the transistor Mp is turned on, theresistor array Rpa can be equivalent to connect to the resistor 1338 inparallel, which reduces the equivalent impedance to lower than theresistor 1338 alone. The lower equivalent resistance then can match anorder of magnitude of the body impedance. Therefore, during theinstallation detection mode, when the LED tube lamp isimproperly/incorrectly installed (e.g., a user touches the conductivepart of the LED tube lamp, or an external impedance is electricallyconnected to a power loop of the LED tube lamp), the introduction of theresistor array Rpa can adjust the equivalent impedance and thus increasethe amount of variation in the current detection signal I_(SEN). As aresult, the sensibility of reflecting the body impedance can beenhanced, and thereby improving the accuracy of the installationdetection result.

FIG. 32 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments. Referring to FIG. 32,the LED tube lamp 1400 is, for example, configured to receive anexternal driving signal directly provided by an external AC power source508, wherein the external driving signal is input through the live wire(marked as “L”) and the neutral wire (marked as “N”) to two pins 501 and502 on two ends of the LED tube lamp 1400. In practical applications,the LED tube lamp 1400 may further have two additional pins 503 and 504,also on the two ends. Under the structure of the LED tube lamp 1400having the four pins 501-504, depending on design needs two pins (suchas the pins 501 and 503, or the pins 502 and 504) on an end cap coupledto one end of the LED tube lamp 1400 may be electrically connected ormutually electrically independent, but the invention is not limited toany of the mentioned cases. A shock detection module 6000 is disposedinside the LED tube lamp 1400 and includes a detection control circuit6100 and a current-limiting circuit 6200. The shock detection module6000 may be and is hereinafter referred to as an installation detectionmodule 6000. The current-limiting circuit 6200 may be disposed incombination with a driving circuit 530, and may be the driving circuit530 itself or may comprise a bias adjustment circuit (to be furtherdescribed in embodiments below) configured for controlling theenabling/disabling of the driving circuit 530. The detection controlcircuit 6100 is electrically connected to a power loop of the LED tubelamp 1400 through a first detection connection terminal DE1 and a seconddetection connection terminal DE2, in order to sample and detect, undera detection mode, a signal on the power loop, and is configured tocontrol the current-limiting circuit 6200 according to the detectionresult, so as to determine whether to prevent a current from passingthrough the LED tube lamp 1400. When the LED tube lamp 1400 is not yetcorrectly/properly installed into a lamp socket, the detection controlcircuit 6100 detects a relatively small current signal and thenassumes/presumes it to be facing or passing through relatively highimpedance, so the current-limiting circuit 6200 in response disables thedriving circuit 530 to prevent the LED tube lamp 1400 from operating ina normal lighting mode (i.e., suspending the LED tube lamp 1400 fromlighting up). On the other hand, when a relatively large current signalis detected or a relatively small current signal is not detected, thedetection control circuit 6100 determines that the LED tube lamp 1400 iscorrectly/properly installed into a lamp socket, and then thecurrent-limiting circuit 6200 allows the LED tube lamp 1400 to operatein a normal lighting mode (i.e., allowing the LED tube lamp 1400 beinglighted up) by enabling the driving circuit 530. In some embodiments,when a current signal on the power loop sampled and detected by thedetection control circuit 6100 is equal to or higher than a defined orset current value, the detection control circuit 6100 determines thatthe LED tube lamp 1400 is correctly/properly installed into a lampsocket and then causes the current-limiting circuit 6200 to enable thedriving circuit 530. But when the current signal sampled and detected bythe detection control circuit 6100 is lower than a defined or setcurrent value, the detection control circuit 6100 determines that theLED tube lamp 1400 is not correctly/properly installed into a lampsocket and thus causes the current-limiting circuit 5200 to disable thedriving circuit 530, thereby causing the LED tube lamp 1400 to enterinto a non-conducting state or limiting an effective current value on apower loop in the LED tube lamp 1400 to being smaller than, for example,5 mA (or 5MIU according to certain certification standards). Theinstallation detection module 6000 can be regarded as determiningwhether to cause current conduction or cutoff of the current-limitingcircuit 6200 based on the detected impedance, thereby causing the LEDtube lamp 1400 to operate in a conducting or normally driven state orenter into a current-limited state or non-driven state. Accordingly, anLED tube lamp 1400 using such an installation detection module 6000 hasthe benefit of avoiding or reducing the risk of electric shock hazardoccurring on the body of a user when accidentally touching or holding aconducting part of the LED tube lamp 1400 which is not yetcorrectly/properly installed into a lamp socket.

Specifically, when (part of) a human body touches or contacts an LEDtube lamp, some impedance of the human body may cause a change inequivalent impedance on a power loop in the LED tube lamp, so theinstallation detection module 6000 can determine whether a human bodyhas touched or contacted the LED tube lamp by e.g. detecting a change incurrent/voltage on the power loop, in order to implement the function toprevent electric shock. The installation detection module 6000 of thepresent embodiment can determine whether the LED tube lamp iscorrectly/properly installed into a lamp socket or whether the body of auser has accidentally touched a conducting part of the LED tube lampwhich is not yet correctly/properly installed into a lamp socket, bydetecting an electrical signal such as a voltage or current. Further,compared to the embodiments of FIGS. 14 and 25, since a signal used fordetermining the installation state is detected/sampled, by the detectioncontrol circuit 6100, from the input side of the rectifying circuit 510,the signal characteristics may not be easily influenced by othercircuits in the power supply module, so that the possibility ofmisoperation of the detection control circuit 6100 can be reduced.

From circuit operation perspectives, a method performed by the detectioncontrol circuit 6100 and configured to determine under a detection modewhether the LED tube lamp 1400 is correctly/properly installed to a lampsocket or whether there is any unintended external impedance beingconnected to the LED tube lamp 1400 is shown in FIG. 44A. The methodincludes the following steps: temporarily conducting a detection pathfor a period and then cutting it off (step S101); sampling an electricalsignal on the detection path during the conduction period (step S102);determining whether the sample of electrical signal conforms withpredefined signal characteristics (step S103); if the determinationresult in step S103 is positive, controlling the current-limitingcircuit 5200 to operate in a first state (step S104); and if thedetermination result in step S103 is negative, controlling thecurrent-limiting circuit 6200 to operate in a second state (step S105)and then returning to the step S101.

In the method of FIG. 44A performed in the embodiment of FIG. 32, thedetection path can be a current path connected between the input side ofthe rectifying circuit 510 and a ground terminal, and its detailedcircuit configurations in the embodiment are presented and illustratedbelow with reference to FIGS. 33A-33C. In addition, the detaileddescription of how to set parameters such as the conduction period,intervals between multiple conduction periods, and the time point totrigger conduction, of the detection path in the detection controlcircuit 6100 can refer to the relevant embodiments described in thedisclosure.

In the step S101, conducting the detection path for a period may beimplemented by means using pulse signal to control switching of aswitch.

In the step S102, the sample of an electrical signal is a signal thatcan represent or express impedance variation on the detection path,which signal may comprise a voltage signal, a current signal, afrequency signal, a phase signal, etc.

In the step S103, the operation of determining whether the sampledelectrical signal conforms to predefined signal characteristics maycomprise, for example, a relative relation of the sampled electricalsignal to a predefined signal. In some embodiments, the sampledelectrical signal that is determined by the detection control circuit6100 to conform to the predefined signal characteristics may correspondto a determination or state that the LED tube lamp 1400 iscorrectly/properly connected to the lamp socket or there is nounintended external impedance being coupled to the LED tube lamp 1400,and the sampled electrical signal that is determined by the detectioncontrol circuit 4100 to not conform to the predefined signalcharacteristics may correspond to a determination or state where the LEDtube lamp 1400 is not correctly/properly connected to the lamp socket orthere is a foreign external impedance (e.g., a human body impedance,simulated/test human body impedance, or other impedance connected to thelamp and which the lamp is not designed to connect to for properlighting operations) being coupled to the LED tube lamp 1400.

In the steps S104 and S105 performed in the embodiment of FIG. 25, thefirst state and the second state are two distinct circuit-configurationstates, and may be set according to the configured position and type ofthe current-limiting circuit 6200. For example, in the case orembodiment where the current-limiting circuit 6200 refers to a biasadjustment circuit connected to a power supply terminal or enableterminal of a controller of the driving circuit 530, the first state isa cutoff state (or normal bias state, which allows the driving voltageto be normally supplied to the driving controller) while the secondstate is a conducting state (or bias adjustment state, which suspendsthe driving voltage from being supplied to the driving controller). Andin the case or embodiment where the current-limiting circuit 6200 refersto a power switch in the driving circuit 530, the first state is adriving-control state, where switching of the current-limiting circuit6200 is only controlled by the driving controller in the driving circuit530 and not affected by the detection control circuit 6100; while thesecond state is a cutoff state.

Detailed operations and example circuit structures for performing theabove method in FIG. 44A as under the structure of FIG. 25 areillustrated by descriptions herein of different embodiments of aninstallation detection module.

Similar to the described embodiments of FIG. 25, the LED tube lamp 6000of FIG. 32 may further include a flicker suppression circuit 590,wherein configurations and operations of such an LED tube lamp 6000 aresimilar to those of the embodiments of FIG. 25, and so are not describedagain here.

FIG. 33A is a block diagram of an installation detection moduleaccording to some exemplary embodiments. Referring to FIG. 33A, theinstallation detection module 6000 a includes a detection pulsegenerating module 6110, a control circuit 6120, a detection determiningcircuit 6130, and a detection path circuit 6160. The detectiondetermining circuit 6130 is coupled to the detection path circuit 6160via a path 6161, in order to detect a signal on the detection pathcircuit 6160. The detection determining circuit 6130 is coupled to thecontrol circuit 6120 via a path 6131, in order to transmit a detectionresult signal to the control circuit 6120 via the path 6131. Thedetection pulse generating module 6110 is coupled to the detection pathcircuit 6160 via a path 6111, in order to generate a pulse signal toinform the detection path circuit 6160 of a time point to conduct adetection path or perform the installation detection. And the controlcircuit 6120 is coupled to a driving circuit 1430 through a path 6121,in order to control operations of the driving circuit 1430 according tothe detection result signal.

In the present embodiment, the detection path circuit 6160 has a firstdetection connection terminal DE1, a second detection connectionterminal DE2, and a third detection connection terminal DE3, wherein thefirst detection connection terminal DE1 and second detection connectionterminal DE2 are electrically connected to two input terminals of arectifying circuit 510 respectively, in order to receive or sample anexternal driving signal through a first pin 501 and a second pin 502.The detection path circuit 6160 is configured to rectify thereceived/sampled external driving signal and to determine under thecontrol of the detection pulse generating module 6110 whether to conductthe rectified external driving signal through a detection path. Forexample, the detection path circuit 6160 is configured to determinewhether to conduct the detection path, in response to the control of thedetection pulse generating module 6110. Detailed circuit operations suchas using pulse signal for conducting the detection path and detectingwhether there is any extraneous impedance being connected to aconductive part of the LED tube lamp are similar to those described inthe embodiments of FIGS. 19B-19D, and thus are not repeatedly describedhere again. Further, detailed configurations and operations of thedetection pulse generating module 6110 and the detection determiningcircuit 6130 of FIG. 33A can be seen by referring to the descriptionsherein of other analogous embodiments, and thus are not repeatedlydescribed again.

From the perspective of the overall operation of the installationdetection module 6000 a, when the LED tube lamp is initially powered up,the detection pulse generating module 6110 is enabled/activated inresponse to the provided external power and generates a pulse signal totemporarily turn on or conduct the detection path formed by thedetection path circuit 6160. During the period that the detection pathis conducted, the detection determining circuit 6130 samples a signal onthe detection path and determines whether the LED tube lamp is correctlyinstalled in the lamp socket or whether a leakage current is generatedby a user touching a conductive part of the LED tube lamp. The detectiondetermining circuit 6130 generates a corresponding detection resultsignal, according to the determination result, and transmits it to thecontrol circuit 6120.

In some embodiments, the control circuit 6120 may comprise a circuitconfigured to transmit a control signal to a controller in the drivingcircuit 1430. In the present embodiment, when the control circuit 6120receives a detection result signal indicating that the LED tube lamp hasbeen correctly installed in the lamp socket, the control circuit 6120transmits a corresponding control signal to the driving circuit 1430,allowing the driving circuit 1430 to normally perform power conversionfor supplying an LED module. On the other hand, when the control circuit6120 receives a detection result signal indicating that the LED tubelamp is not correctly installed in the lamp socket, the control circuit6120 transmits a corresponding control signal to the driving circuit1430, causing the driving circuit 1430 to, in response to the controlsignal, stop its normal operation or to be disabled. In this case, whenthe driving circuit 1430 is disabled, the current flowing through thepower loop can usually be limited to being lower than a safety value(e.g., 5 MIU).

In some embodiments, the control circuit 6120 comprises and may bereferred to below as a bias adjustment circuit 6120, which can controlthe operation state of the driving circuit 1430 by affecting oradjusting a bias voltage of the driving circuit 1430. In the presentembodiment, when the bias adjustment circuit 6120 receives a detectionresult signal indicating that the LED tube lamp has been correctlyinstalled in the lamp socket, the bias adjustment circuit 6120 does notadjust the bias voltage of the driving circuit 1430, and therefore thedriving circuit 1430 can be normally enabled by a received bias voltageand can perform power conversion to provide electricity to the LEDmodule. On the contrary, when the bias adjustment circuit 6120 receivesa detection result signal indicating that the LED tube lamp is notcorrectly installed in the lamp socket, the bias adjustment circuit 6120adjusts the bias voltage provided to the driving circuit 1430, to alevel that is not capable of enabling the driving circuit 1430 tonormally perform power conversion. In this case, since the drivingcircuit 1430 is disabled, the current flowing through the power loop canbe limited to lower than the safety value.

Under the configuration of the control circuit 6120, the switchingcircuit (such as each of the switching circuits 3200, 3200 a-L, 4200,and 4200 a) disposed on the power loop and thus required to withstandhigh current, can be omitted, and therefore the cost of the overallinstallation detection module can be significantly reduced. On the otherhand, since the leakage current is limited by controlling the biasvoltage of the driving circuit 1430 through the control circuit 6120,the circuit design of the driving circuit 1430 does not need to bechanged, so as to make the commercialization easier.

In an exemplary embodiment, the detection pulse generating module 6110and the detection path circuit 6160 can be respectively implemented by,but not limited to, the circuit configurations illustrated in FIGS. 33Band 33C, and the circuit configurations of the other circuits of theinstallation detection module 6000 a are similar to those of thecounterpart circuits in other analogous embodiments described herein.Detailed descriptions of the module(s) and circuits illustrated by FIGS.33B and 33C are presented below.

FIG. 33B is a schematic circuit diagram of the detection pulsegenerating module according to some embodiments. Referring to FIG. 33B,the detection pulse generating module 6110 includes resistors Rd1 andRd2, a capacitor Cd1 and a pulse generating circuit 6112. Theconfiguration of the embodiment illustrated in FIG. 31B is similar tothat of the detection pulse generating module 5110, the differencebetween these two embodiments is that the first end of the resistor Rd1is electrically connected to the first rectifying input terminal(represented as the pin 501) via the diode Dd1 and to the secondrectifying input terminal (represented as the pin 502) via the diodeDd2.

FIG. 33C is a schematic circuit diagram of the detection path circuitaccording to some embodiments. Referring to FIG. 33C, the detection pathcircuit 6160 includes a resistor Rd3, a transistor Md1 and diodes Dd1and Dd2. The configuration of the embodiment illustrated in FIG. 33C issimilar to that of the detection path circuit 5160, and the differencebetween these two embodiments is the detection path circuit 6160 furtherincludes the diodes Dd1 and Dd2, and the first end of the resistor Rd3is electrically connected to the first rectifying input terminal(represented as the pin 501) via the diode Dd1 and to the secondrectifying input terminal (represented as the pin 502) via the diodeDd2. In this manner, a detection path can be formed between therectifying input terminal and the rectifying output terminal, which canbe referred to a branch circuit extending from the power loop and is acurrent path substantially independent from the power loop. Theconfiguration and operation of the diodes Dd1 and Dd2 can be seenreferring to the embodiment illustrated in FIG. 24B, and it will not berepeated herein.

It should be noted that, although the transistor M51 is illustrated as aBJT for example, the invention is not limited thereto. In someembodiments, the transistor M51 can be implemented by a MOSFET. Whenutilizing the MOSFET as the transistor M51, the gate of the transistorM51 is connected to the detection pulse generating module 3510 via thepath 3511. The resistor M51 is serially connected between the source ofthe transistor M51 and the ground. The resistor R51 is seriallyconnected between the drain of the transistor M51 and the installationdetection terminal TE1.

In addition, although the sample node X is selected from the firstterminal of the transistor M51 for example, in which the first terminalis the collector terminal if the transistor M51 is BJT and the firstterminal is the drain terminal if the transistor M51 is MOSFET, thepresent invention is not limited thereto. The sample node X can beselected from the second terminal of the transistor M51 as well, inwhich case the second terminal is the emitter terminal if the transistorM51 is BJT and the second terminal is the source terminal if thetransistor M51 is MOSFET. As a result, the detection determining circuit3530 can detects the signal feature on at least one of the firstterminal and the second terminal of the transistor M51.

As noted above, the present embodiment may determine whether a user hasa chance to get an electric shock by conducting a detection path anddetecting a voltage signal on the detection path. Compared to theembodiment mentioned above, the detection path of the present embodimentis additionally built, but does not use the power loop as the detectionpath. In some embodiments, the additional detection path refers to atleast one electronic element of the detection path circuit 3560 beingdifferent from electronic elements included in the power loop. In someembodiments, the additional detection path refers to all of theelectronic elements of the detection path circuit 3560 being differentfrom electronic elements included in the power loop.

Since the configuration of the components on the additional detectionpath is much simpler than the power loop, the voltage signal on thedetection path may reflect a user's touching state more accurately.

Furthermore, similar to the above embodiment, part or all of thecircuit/module can be integrated as a chip, as illustrated in theembodiments in FIG. 17A to FIG. 18F, and it will not be repeated herein.

For describing operations or working mechanisms of the installationdetection module in concrete detail, in some disclosed embodiments, thecircuit components of the installation detection module can becategorized into different functional modules, including, for example, adetection pulse generating module, a detection result latching circuit,a detection determining circuit, a detection control circuit, and aswitch circuit/current limiting circuit/bias adjustment circuit. Butelements of actual designed embodiments of the installation detectionmodule are not limited to the described modules herein. For example, inone perspective as shown in FIG. 34, circuits in an installationdetection module 7000 and related to detecting an installation state andperforming switching control can be integrated into or generallyreferred to as a detection controller 7100; and circuits in aninstallation detection module 7000 and related to responding to controlby the detection controller 7100 and therefore affecting magnitude ofcurrent on a power loop can be integrated into or generally referred toas a current limiting module 7200. Furthermore, although not pointed outin the described example embodiments, a person of ordinary skill in therelevant art can naturally understand that any circuit includingelements requiring power supply to operate needs at least onecorresponding driving voltage (e.g., VCC) to operate, and thus thatthere will be some element(s) or circuit line(s) in the installationdetection module that are for the purpose of generating the drivingvoltage VCC. In the embodiment of FIG. 34, circuits in an installationdetection module and for generating the driving voltage VCC areintegrated into or generally referred to as bias circuit 7300.

Under the functional modules in the embodiment of FIG. 34, the detectioncontroller 7100 is configured to perform an installation detection (oran impedance detection), so as to determine whether the LED tube lamp isor has been correctly/properly connected to the lamp socket or whetherthere is any extraneous or unintended external impedance (such as humanbody impedance) intervening in or coupling to a circuit of the LED tubelamp, wherein the detection controller 7100 will control the currentlimiting module 7200 according to the determination result. If thedetection controller 7100 determines that the LED tube lamp is notcorrectly/properly connected to the lamp socket or there is extraneousor unintended external impedance intervening in, the detectioncontroller 7100 controls cut off of the current limiting module 7200, toprevent a current on a power loop of the LED tube lamp from beingexcessive to cause an electric shock. The current limiting module 7200is configured to cause a current to normally flow on the power loop,when the detection controller 7100 determines that the LED tube lamp iscorrectly/properly connected to the lamp socket or there is no suchunintended impedance; and is configured to cause a current on the powerloop to be below a certain level to prevent the current from exceedingthe safety value, when the detection controller 7100 determines that theLED tube lamp is not correctly/properly connected to the lamp socket orthere is such unintended impedance. In circuit design or configuration,the current limiting module 7200 may be independent of the drivingcircuit (such as 530) and may comprise a switch circuit or a currentlimiting circuit connected to the power loop in series (such as each ofcurrent-limiting circuits 3200, 3200 a-L4200, and 4200 a, in FIGS. 15A,16A, 17A, 18A, 19A, 22A, 22B, 23, 24A, and 24B), a bias adjustmentcircuit connected to a power supply terminal or enable terminal of acontroller of the driving circuit (such as a bias adjustment circuit5200A in FIG. 27A), a power switch in the driving circuit (such as aswitch circuit 635, 1035, 1135, 1535 in FIG. 26G, 30B), or a switchcircuit in a flicker suppression circuit (such as a switch circuit 694of flicker suppression circuit 690 in FIG. 28B). The bias circuit 7300is configured for providing a driving voltage VCC required for operationof the detection controller 7100, and embodiments of the bias circuit7300 can be described hereinafter with reference to FIGS. 35B and 35C.

From functional perspectives, the detection controller 7100 may beregarded as detection control means used by the installation detectionmodule of the present disclosure, and the current limiting module 7200may be regarded as switching means or current limiting means used by theinstallation detection module of this disclosure, wherein the detectioncontrol means may correspond to partial or all circuits of theinstallation detection module and other than the switching means, andthe switching means may correspond to any one of possible circuitembodiment types of the above described current limiting module 7200.

From circuit operation perspectives, a method performed by the detectioncontroller 7100 and configured to determine whether the LED tube lamp iscorrectly/properly connected to the lamp socket or whether there is anyunintended external impedance being connected to the LED tube lamp isshown in FIG. 44A. The method includes the following steps: temporarilyconducting a detection path for a period and then cutting it off (stepS101); sampling an electrical signal on the detection path (step S102);determining whether the sampled electrical signal conforms withpredefined signal characteristics (step S103); if the determinationresult in step S103 is positive, controlling the current limiting module7200 to be operated in a first state (step S104); and if thedetermination result in step S103 is negative, controlling the currentlimiting module 7200 to be operated in a second state (step S105) andthen returning to the step S101.

Configuration of the detection path and setting of the conduction periodof the detection path can be done with reference to the above describedembodiments. In the step S101, conducting the detection path for aperiod may be implemented by means using pulse to control switching of aswitch.

In the step S102, the sampled electrical signal is a signal that canrepresent or express impedance variation on the detection path, whichmay comprise a voltage signal, a current signal, a frequency signal, aphase signal, etc.

In the step S103, the operation of determining whether the sampledelectrical signal conforms with predefined signal characteristics maycomprise, for example, a relative relation of the sampled electricalsignal and a predefined signal. In some embodiments, the sampledelectrical signal that is determined to conform with the predefinedsignal characteristics may correspond to a determination or state thatthe LED tube lamp is correctly/properly connected to the lamp socket orthere is no unintended external impedance being coupled to the LED tubelamp, and the sampled electrical signal that is determined to notconform with the predefined signal characteristics may correspond to adetermination or state where the LED tube lamp is not correctly/properlyconnected to the lamp socket or there is a foreign external impedance(e.g., a human body impedance, simulated/test human body impedance, orother impedance connected to the lamp and which the lamp is not designedto connect to for proper lighting operations) being coupled to the LEDtube lamp.

In the steps S104 and S105, the first state and the second state are twodistinct circuit-configuration states, and may be set according to theconfigured position and type of the current limiting module 7200. Forexample, in the case or embodiment where the current limiting module7200 is independent of the driving circuit and refers to a switchcircuit or a current limiting circuit that is serially connected on thepower loop, the first state is a conducting state (ornon-current-limiting state) while the second state being a cutoff state(or current-limiting state). In the case or embodiment where the currentlimiting module 7200 refers to a control circuit connected to a powersupply terminal or enable terminal of a controller of the drivingcircuit, the first state is a cutoff state (or normal bias state, whichallows the driving voltage being normally supplied to the controller)while the second state is a conducting state (or bias adjustment state,which suspends the driving voltage from being supplied to thecontroller). And in the case or embodiment where the current limitingmodule 7200 refers to a power switch in the driving circuit, the firststate is a driving-control state, which switches in response to thecontroller of the driving circuit and does not affect the detectioncontroller 7100; while the second state is a cutoff state.

Detailed operations and circuit embodiments of the steps described inconnection with FIGS. 41A-41C are exemplified by and described in theabove description of embodiments and the steps serve to describeoperation mechanism of the installation detection module in a differentmanner.

Next, operations of the installation detection module after enteringinto the LED operating mode DRM are further described here withreference to the steps in FIG. 44C. Referring to FIGS. 34 and 44C, afterentering into the LED operating mode DRM, the detection controller 7100performs following steps: detecting a bus voltage on the power line(step S301); and determining whether the voltage on the power lineremains below a third voltage level for a second period (step S302). Thesecond period is for example in the range of 200 ms-700 ms, and ispreferably 300 ms or 600 ms. The third voltage level is for example inthe range of 80V-120V, and is preferably 90V or 115V. Thus in someembodiments of the step S302, the detection controller 7100 determineswhether the voltage on the power line remains below 115V for 600 ms.

If the determination result in step S302 is positive, this indicatesthat the external driving signal is not, or ceases to be, provided tothe LED tube lamp, or that the LED tube lamp is powered off, so thedetection controller 7100 proceeds to perform the two steps of:controlling to switch the current limiting module 7200 into the secondstate (step S303) and then resetting the detection controller 7100 (stepS304). On the other hand, if the determination result in step S302 isnegative, this indicates or can be regarded as that the external drivingsignal is normally provided to the LED tube lamp, so the detectioncontroller 7100 proceeds back to step S301 where it continually detectsthe voltage on the power line to determine whether the LED tube lamp ispowered off.

FIG. 35A is a circuit diagram illustrating a bias circuit with theinstallation detection module according to some embodiments. Referringto FIG. 35A, in an application where the LED tube lamp receives an ACpower as an input, a bias circuit 7300 a includes a rectifying circuit7310, resistors Re1 and Re2, and a capacitor Ce1. In this embodiment,the rectifying circuit 7310 includes a full-wave bridge rectifier as anexample, to which the present invention is not limited. The inputterminals of the rectifying circuit 7310 are configured to receive anexternal driving signal Sed and rectify the external driving signal Sedto output a rectified (nearly) DC signal at the output terminals of therectifying circuit 7310. Resistors Re1 and Re2 are connected in seriesbetween the output terminals of the rectifying circuit 7310, and theresistor Re2 is connected with the capacitor Ce1 in parallel. Therectified signal is divided by the resistor Re1 and Re2 and stabilizedby the capacitor Ce1, so as to generate a driving voltage VCC outputacross two terminals of the capacitor Ce1 (i.e., the node PN and theground terminal).

In an embodiment where the installation detection module is integratedinto the LED tube lamp, since a power supply module in the LED tube lampusually includes its own rectifying circuit (such as 510), therectifying circuit 7310 can be replaced by the existing rectifyingcircuit. And the resistors Re1 and Re2 and the capacitor Ce1 may bedirectly connected on a power loop of the power supply module, such thatthe installation detection module can use the rectified bus voltage(i.e. the rectified signal) on the power loop as a power source. In anembodiment where the installation detection module is disposed outsideof the LED tube lamp, since the installation detection module directlyuses the external driving signal Sed as a power source, the rectifyingcircuit 7310 is separate from the power supply module, and is configuredto convert the AC external driving signal Sed into the DC drivingvoltage VCC to be used by circuits in the installation detection module.

FIG. 35B is a circuit diagram illustrating a bias circuit with theinstallation detection module according to some embodiments. Referringto FIG. 35B, a bias circuit 7300 b includes a rectifying circuit 7310, aresistor Re3, a Zener diode ZD1, and a capacitor Ce2. This embodiment issimilar to that in FIG. 35A, with a main difference that the Zener diodeZD1 is used to replace the resistor Re2 in FIG. 35A, in order to makethe driving voltage VCC more stable.

FIG. 36 is an application circuit block diagram of the detection pulsegenerating module according to some embodiments. Referring to FIG. 36,in this embodiment, a detection pulse generating module 7110 includes apulse starting circuit 7112 and a pulse-width determining circuit 7113.The pulse starting circuit 7112 is configured to receive the externaldriving signal Sed, and to determine when (e.g., at what time, forexample in relation to the time at which the external driving signal Sedwas received) to generate or issue a pulse by the detection pulsegenerating module 7110, according to the external driving signal Sed.The pulse-width determining circuit 7113 is coupled to an outputterminal of the pulse starting circuit 7112 to set or determine width ofthe pulse, and to issue at the determined time indicated by the pulsestarting circuit 7112 a pulse signal DP having the set pulse width.

In some embodiments, the detection pulse generating module 7110 mayfurther comprise an output buffer circuit 7114. An input terminal of theoutput buffer circuit 7114 is coupled to an output terminal of thepulse-width determining circuit 7113. And the output buffer circuit 7114is configured or used to adjust the waveform of an output signal (suchas a voltage or current signal) from the pulse-width determining circuit7113, so as to output the pulse signal DP that can meet operation needsof rear end circuit(s).

Taking the detection pulse generating module 3110 illustrated in FIG.15B as an example, its time at which to issue the pulse signal isdetermined based on when it receives the driving voltage, so a biascircuit that generates the driving voltage VCC can be regarded as apulse starting circuit of the detection pulse generating module 3110. Inanother respect, the pulse width of the pulse signal generated or issuedby the detection pulse generating module 3110 is mainly determined bythe time constant of an RC charging-discharging circuit composed of thecapacitors C11, C12, and C13, and the resistors R11, R12, and R13. Sothe capacitors C11, C12, and C13, and the resistors R11, R12, and R13can together be regarded as a pulse-width determining circuit of thedetection pulse generating module 3110. And the buffers BF1 and BF2 canbe an output buffer circuit of the detection pulse generating module3110.

Taking the detection pulse generating module 3210 illustrated in FIG.16B as another example, its time at which to issue the pulse signal isdetermined based on the time at which it receives the driving voltageVCC in FIG. 16B and related to the time constant of an RCcharging-discharging circuit composed of the resistor R21 and thecapacitor C21. So a bias circuit that generates the driving voltage VCC,the resistor R21, and the capacitor C21 can together be regarded as apulse starting circuit of the detection pulse generating module 3210. Inanother respect, the pulse width of the pulse signal generated or issuedby the detection pulse generating module 3210 is mainly determined bythe forward threshold voltage and reverse threshold voltage of theSchmitt trigger STRG and the switching latency of the transistor M21, sothe Schmitt trigger STRG and the transistor M21 can together be regardedas a pulse-width determining circuit of the detection pulse generatingmodule 3210.

In some embodiments, a pulse starting circuit of the detection pulsegenerating module 3110 or 3210 can implement the control of the pulsestarting time (or the time at which to issue the pulse signal) byincluding a comparator as shown in FIG. 37A. FIG. 37A is a circuitdiagram illustrating a detection pulse generating module according tosome embodiments. Referring to FIG. 37A, specifically, a detection pulsegenerating module 7110 a includes a comparator 7112 a, as a pulsestarting circuit, and a pulse-width determining circuit 7113 a. Thecomparator 7112 a has a first input terminal to receive an externaldriving signal Sed, a second input terminal to receive a referencevoltage level Vps, and an output terminal connected to an end of aresistor Rf1, which end corresponds to the input terminal of drivingvoltage VCC in FIG. 16B. Here, the comparator 7112 a's receiving of theexternal driving signal Sed is not limited to the way of inputting theexternal driving signal Sed directly to the first input terminal of thecomparator 7112 a. In some embodiments, the external driving signal Sedmay first undergo some signal processing such as rectification and/orvoltage division to be transformed to a state signal related to theexternal driving signal Sed, and the state signal then is inputted tothe comparator 7112 a. The comparator 7112 a then learns about the stateof the external driving signal Sed according to the state signal, whichway is equivalent to the comparator 7112 a directly receiving theexternal driving signal Sed or performing its following step of signalcomparison based on the external driving signal Sed. The pulse-widthdetermining circuit 7113 a includes resistors Rf1, Rf2, and Rf3, aSchmitt trigger STRG, a transistor Mf1, a capacitor Cf1, and a Zenerdiode ZD1, wherein configuration of these devices is similar to that inFIG. 16B and therefore description of connections between these devicesis referred to such descriptions of embodiments above. Under theconfiguration of FIG. 37A, an RC circuit composed of the capacitor Cf1and the resistor Rf1 begins to charge the capacitor Cf1 only upon avoltage level of the external driving signal Sed exceeding the referencevoltage level Vps, to in turn control the time to issue the pulse signalDP. Corresponding variations of three relevant signals along the timeaxis are shown in FIG. 39A.

Referring to FIGS. 37A and 39A, in this embodiment of FIG. 37A, thecomparator 7112 a as a pulse starting circuit outputs a high-levelsignal to an end of the resistor Rf1 to begin charging the capacitorCf1, whose voltage Vcp gradually increases over time during thecharging. When the voltage signal Vcp reaches the forward thresholdvoltage Vsch1 of the Schmitt trigger STRG, the Schmitt trigger STRG'soutput terminal outputs a high-level signal, which in turn conducts thetransistor Mf1. Upon the conducting of the transistor Mf1, the capacitorCf1 begins discharging to ground through the resistor Rf2 and thetransistor Mf1, so as to gradually decrease the voltage signal Vcp. Whenthe decreasing voltage signal Vcp reaches the reverse threshold voltageVsch2 of the Schmitt trigger STRGz, the Schmitt trigger STRG's outputterminal switches from outputting the high-level signal to outputting alow-level signal, thus forming/generating the pulse signal or waveformDP1, whose pulse width DPW is determined by the forward thresholdvoltage Vsch1, the reverse threshold voltage Vsch2, and the switchinglatency of the transistor Mf1. Upon forming the pulse signal DP1,another similar pulse signal or waveform DP2 is similarly generated bythe Schmitt trigger STRG after an interval TIV, in which the intervalTIV can be defined by a duration that the voltage signal Vcp falls fromless than the reverse threshold voltage Vsch2 to higher than the forwardthreshold voltage Vsch1 again. Generation of such similar pulse signals(DP2, DP3, and etc) may similarly follow.

In some embodiments, the pulse starting circuit 7112 indicates the timeto generate or issue a pulse signal, thereby determining the time togenerate the pulse signal by the detection pulse generating module 7110,when the external driving signal Sed reaches or exceeds a specificvoltage level, as implemented by an embodiment in FIG. 37B. FIG. 37B isa circuit diagram illustrating a detection pulse generating moduleaccording to some embodiments. Referring to FIG. 37B, specifically, adetection pulse generating module 7110 b includes a pulse startingcircuit 7112 b and a pulse-width determining circuit 7113 b. The pulsestarting circuit 7112 b includes a comparator CPf1 and a signal edgetriggering circuit SETC. The comparator CPf1 has a first input terminalto receive an external driving signal Sed, a second input terminal toreceive a reference voltage level Vps, and an output terminal connectedto an input terminal of the signal edge triggering circuit SETC. Thesignal edge triggering circuit SETC may for example comprises arising-edge triggering circuit or a falling-edge triggering circuit,configured to detect the time of the comparator CPf1 switching itsoutput state, and then to transmit an instruction to generate a pulsesignal for the later-stage pulse-width determining circuit 7113 b. Thepulse-width determining circuit 7113 b may comprise any kind of pulsegenerating circuit that capable of generating, according to the pulsegeneration instruction, a pulse signal with a set width at a specifictime, such as the circuits in each of FIG. 15B and FIG. 16B, or anintegrated device like a 555 timer, and this invention is not limited tothese example circuits. It's noted that although in FIG. 37B it'sillustrated that the comparator CPf1's first input terminal directlyreceives an external driving signal Sed, this invention is not limitedto this example. In some embodiments, the external driving signal Sedmay first undergo some signal processing such as rectification,filtering, and/or voltage division to be a reference signal and thenreceived by the first input terminal of the comparator CPf1. Thus, thepulse starting circuit 7112 b can determine the time at which togenerate a pulse signal based on a received reference signal related toor indicative of the voltage level or phase state of the externaldriving signal Sed.

Corresponding variations of three relevant signals along the time axisgenerated in the embodiment of the detection pulse generating module3610 in FIG. 20A are shown in each of FIG. 39B and FIG. 39C, whereinFIG. 39B shows waveforms of the three signals generated under the risingedge-triggered method and FIG. 39C shows waveforms of the three signalsgenerated under the falling edge-triggered method. Referring to FIG. 37Band FIG. 39B, in this embodiment under the rising edge-triggered method,the comparator CPf1 begins outputting a high-level signal upon a voltagelevel of the external driving signal Sed exceeding a reference voltagelevel Vps, and the output is maintained at the high level for theduration that the external driving signal Sed is above the referencevoltage level Vps. When the external driving signal Sed graduallydecreases from its peak value and upon its falling below the referencevoltage level Vps, the comparator CPf1 switches into outputting alow-level signal (again). Accordingly, the output terminal of thecomparator CPf1 outputs an output voltage signal Vcp as shown in FIG.39B. Around when a rising edge occurs on the voltage signal Vcp, thesignal edge triggering circuit SETC triggers and outputs an enablesignal to the pulse-width determining circuit 7113 b, so that thepulse-width determining circuit 7113 b around the time of the risingedge generates a pulse signal DP having a pulse or waveform DP1,according to the enable signal and a set pulse width DPW of the pulseDP1. According to these described operations, the detection pulsegenerating module 7110 b can adjust the time to generate the pulse DP1of the pulse signal DP by adjusting, or changing the setting of, thereference voltage level Vps, so that the detection pulse generatingmodule 7110 b is triggered to generate the pulse DP1 of the pulse signalDP only upon the external driving signal Sed reaching a specific voltagelevel or phase. Therefore, the problem of generating the pulse DP1 ofthe pulse signal DP wrongly around when the external driving signal Sedcrosses a zero voltage level associated with some embodiments mentionedearlier can be prevented by this rising edge-triggered method.

In some embodiments, the reference voltage level Vps may be adjustedaccording to the voltage level of the external driving signal Sed on thepower line, so that the detection pulse generating module can generate apulse DP1 of a pulse signal DP at a time point according to the distinctnominal supply voltage (such as 120V or 277V) of the AC power gridproviding the power line. Thus, no matter what a distinct nominal supplyvoltage of an AC power grid providing the external driving signal is,the portion of a period of the external driving signal Sed on the powerline or detection path of the LED tube lamp for which portion adetection is in a triggered state (for the duration of the pulse on thevoltage signal Vcp) can be adjusted or limited according to the distinctnominal supply voltage, by adjusting the reference voltage level Vps, toimprove accuracy of the installation detection or impedance detection.For example, the reference voltage level Vps may comprise a firstreference voltage level corresponding to a first nominal supply voltagesuch as 120V of an AC power grid and a second reference voltage levelcorresponding to a second nominal supply voltage such as 277V of anotherAC power grid. When the external driving signal Sed received by thedetection pulse generating module 7110 b has the first nominal supplyvoltage, the pulse starting circuit 7112 b determines the time at whichto generate a pulse DP1 of the pulse signal DP based on the firstreference voltage level of the reference voltage level Vps. When theexternal driving signal Sed received by the detection pulse generatingmodule 7110 b has the second nominal supply voltage, the pulse startingcircuit 7112 b determines the time at which to generate a pulse DP1 ofthe pulse signal DP based on the second reference voltage level of thereference voltage level Vps.

Referring to FIG. 37B and FIG. 39C, operations in this embodiment underthe falling edge-triggered method are similar to those in the embodimentof FIG. 37B and FIG. 39B, with the main difference that under thefalling edge-triggered method the signal edge triggering circuit SETCtriggers and outputs an enable signal to the pulse-width determiningcircuit 7113 b around when a falling edge occurs on the voltage signalVcp, so the pulse-width determining circuit 7113 b around the time ofthe falling edge generates a pulse signal DP having a pulse or waveformDP1. In some embodiments under the falling edge-triggered method, thereference voltage level Vps may comprise a first reference voltagelevel, such as 115V, corresponding to a first nominal supply voltagesuch as 120V of an AC power grid and a second reference voltage level,such as 200V, corresponding to a second nominal supply voltage such as277V of another AC power grid. When the external driving signal Sedreceived by the detection pulse generating module 7110 b has the firstnominal supply voltage, the pulse starting circuit 7112 b determines togenerate a pulse DP1 of the pulse signal DP when the external drivingsignal Sed falls below the first reference voltage level of 115V. Whenthe external driving signal Sed received by the detection pulsegenerating module 7110 b has the second nominal supply voltage, thepulse starting circuit 7112 b determines to generate a pulse DP1 of thepulse signal DP when the external driving signal Sed falls below thesecond reference voltage level of 200V.

Based on the above teachings and embodiments, a person of ordinary skillin the relevant art can understand that apart from the signal-edgetriggering operations above, various possible mechanisms for determiningthe time to generate a pulse signal DP may be implemented by the pulsestarting circuit 7112. For example, the pulse starting circuit 7112 maybe designed to start recording time upon detecting a rising edge or afalling edge occurring on the voltage signal Vcp, and to trigger andoutput an enable signal to the pulse-width determining circuit 7113 whenthe recorded time reaches a predefined duration. Another example is thatthe pulse starting circuit 7112 may be designed to activate thepulse-width determining circuit 7113 in advance when the pulse startingcircuit 7112 detects a rising edge occurring on the voltage signal Vcp,and to trigger and output an enable signal to the pulse-widthdetermining circuit 7113 when later detecting a falling edge occurringon the voltage signal Vcp, for the early-activated pulse-widthdetermining circuit 7113 to be able to quickly respond in order togenerate the pulse signal DP at an accurate time point.

Corresponding variations of two relevant signals along the time axisgenerated in some embodiments of the detection pulse generating moduleare shown in FIG. 39D. Referring to FIG. 39D, operations in thisembodiment are similar to those in the embodiments of FIG. 39B and FIG.39C, with the main difference that in this embodiment the pulse startingcircuit 7112 is designed to start recording time upon the externaldriving signal Sed exceeding a reference voltage level Vps, and totrigger so as to generate a pulse DP1 of a pulse signal DP when therecorded time reaches a delay duration DLY. Upon generating the pulseDP1, after an interval TIV shown in FIG. 39D, another similar pulse orwaveform DP2 is generated by the detection pulse generating module,which can be followed by similar operations of pulse generation.

Referring to FIG. 34 again, in some embodiments, the installationdetection module 7000 further includes a ballast detection module 7400(similar to the ballast detection module 3400 of FIG. 15A or the ballastdetection module 4400 of FIG. 24A), which is configured for determiningthe type of an external driving signal input to the LED tube lamp of theinstallation detection module 7000, to determine for example whether itis provided by an electronic ballast, and is configured for adjusting away of controlling the current-limiting circuit 7200. For this purpose,the ballast detection module 7400 may be configured to determine whetheran external driving signal Sed currently received by the LED tube lampis an AC signal provided by an electronic ballast or directly by acommercial power grid, by detecting a signal feature of the externaldriving signal Sed or a signal feature of a power line voltage in apower supply module of the LED tube lamp which is derived or followsfrom the external driving signal Sed. Such a signal feature of theexternal driving signal Sed may be one of the electrical signalcharacteristics such as frequency, amplitude, and phase.

In some embodiments, the mentioned adjustment of a way of controllingthe current-limiting circuit 7200 may comprise for example: (1) whenjudging that an external driving signal Sed input to an LED tube lamp isprovided by an electronic ballast, intermittently conducting thecurrent-limiting circuit 7200 to cause the LED tube lamp to flash asmisuse warning, alerting a user that the LED tube lamp might currentlybe installed by mistake to an incompatible lamp socket (as described inthe embodiments of FIG. 15A); or (2) when judging that an externaldriving signal Sed input to a ballast-bypass LED tube lamp is providedby an electronic ballast, shunting or causing a pulse signal used fordetecting installation state to bypass, and maintaining thecurrent-limiting circuit 7200 in a conducting state, in order to enablethe LED tube lamp to light up in response to the input external drivingsignal Sed provided by an electronic ballast.

In the embodiment (2) of adjusting a way of controlling thecurrent-limiting circuit 7200, the LED tube lamp may be of both Type-Aand Type-B, and the specific circuit structure of the ballast detectionmodule 7400 is as illustrated in FIG. 38. FIG. 38 is a circuit diagramof a ballast detection module according to some embodiments. In oneembodiment of FIG. 38, the ballast detection module 7400 includes diodesDh1 and Dh2, a capacitor Ch1, a resistor Rh1, and a voltage regulatingdiode ZDh1. The diodes Dh1 and Dh2 constitute a half-wave rectifyingcircuit, wherein the anode of the diode Dh1 and the cathode of the diodeDh2 are connected in order to receive an external driving signal Sed.The capacitor Ch1 has one end electrically connected to the cathode ofthe diode Dh1, and the other end electrically connected to the anode ofthe diode Dh2. The resistor Rh1, capacitor Ch1, and voltage regulatingdiode ZDh1 are connected in parallel with each other, and the voltageregulating diode ZDh1 is electrically connected to a control terminal ofthe current-limiting circuit 7200. In some embodiments, the ballastdetection module 7400 may further include a diode Dh3, which has ananode electrically connected to the cathode of the voltage regulatingdiode ZDh1 and has a cathode electrically connected to the controlterminal of the current-limiting circuit 7200.

For better concretely explaining operations of the ballast detectionmodule 7400 of the embodiment of FIG. 38, the ballast detection module7400 is below further explained with reference to the signal waveformsin FIG. 41G respectively at the two nodes Nh1 and Nh2 in FIG. 38.Referring to both FIGS. 38 and 41G, when an external driving signal Sedis provided by a commercial AC power grid, since the frequency andvoltage amplitude of a power signal (as the external driving signal Sed)from a commercial AC power grid is relatively low, after undergoinghalf-wave rectification by the diodes Dh1 and Dh2 and voltage regulationby the capacitor Ch1, the rectified and regulated driving signal Sedcauses a small voltage to be generated at the node Nh1, which smallvoltage is not sufficient to cause the voltage regulating diode ZDh1 toenter into a reverse-breakdown state, so the ballast detection module7400 then is equivalent to being in a floating state and does not affectthe state of the signal at the node Nh2. Therefore, no matter whetherthe LED tube lamp is in a normal operation state (i.e. without touchingextraneous impedance) or in a state under a lamp-replacement test (i.e.connected to touching extraneous human-body impedance), thecurrent-limiting circuit 7200 is mainly controlled by a signal output bythe detection control circuit 7100 of FIG. 38.

In another case, when an external driving signal Sed is provided by anelectronic ballast, since the frequency and voltage amplitude of a powersignal (as the external driving signal Sed) from an electronic ballastis relatively low, the voltage at the node Nh1 is or will be greaterthan the breakdown voltage of the voltage regulating diode ZDh1, causingthe voltage regulating diode ZDh1 to enter into a reverse-breakdownstate and causing the voltage at the node Nh2 to be stable at a highvoltage level sufficient to conduct the current-limiting circuit 7200.At this state, an output signal of the detection control circuit 7100 isseen as being shunted or bypassing through the ballast detection module7400, and control of the current-limiting circuit 7200 is taken over bythe ballast detection module 7400. Therefore, even when the LED tubelamp is in a state under a lamp-replacement test (i.e. connected totouching extraneous human-body impedance), a pulse signal output by thedetection control circuit 7100 is or may be shunted by a high voltagelevel signal output by the ballast detection module 7400, causing thecurrent-limiting circuit 7200 to be maintained in a conducting state andnot to intermittently conduct for performing installation detection.

FIG. 40 is a block diagram of an exemplary power supply module in an LEDtube lamp according to some exemplary embodiments. Compared to theembodiment of FIG. 13A, an installation detection module 8000 isdisposed outside of the LED tube lamp 1500 and includes a detectioncontrol circuit 8100 and a current-limiting circuit 8200 which isdisposed on a power line from an external power source 508, and forexample disposed in a lamp socket or fixture. Referring to FIG. 40, whenpins on two ends of the LED tube lamp 1500 are electrically connected tothe external power source 508, the current-limiting circuit 8200 isserially connected on a power loop of the LED tube lamp 1500 through apin 501, causing or enabling the detection control circuit 8100 tojudge, by performing any installation detection method as described inthe embodiments of FIGS. 13A to 39D, whether the LED tube lamp 1500 iscorrectly/properly installed into a lamp socket or whether the body of auser has accidentally touched a conducting part of the LED tube lamp1500 which is not yet correctly/properly installed, and the detectioncontrol circuit 8100 then controls the current-limiting circuit 8200 tolimit power supply from the external power source 508 to the LED tubelamp 1500 when determining that the LED tube lamp 1500 is notcorrectly/properly installed into a lamp socket or there is risk ofelectric shock upon the body of a user touching a conducting part of theLED tube lamp 1500.

It should be noted that, the current-limiting circuits mentioned aboveare embodiments of a means for limiting current, which is configured tolimit the current on the power loop to less than a predetermined value(e.g., 5 MIU) when enabling. People having ordinary skill in the art mayunderstand how to implement the current limiting module by circuitsoperated like a switch according to the embodiments described above. Forexample, the current limiting module can be implemented by electronicswitch (e.g., MOSFET, BJT), electromagnetic switch, relay, triode ACsemiconductor switch (TRIAC), Thyristor, impedance variable component(e.g., variable capacitor, variable resistor, variable inductor) andcombination of the above.

Further, according to the embodiments illustrated in FIG. 16A to 20C,one skilled in the art should understand that the installation detectionmodule illustrated in FIG. 16A can not only be designed as a distributedcircuit applied in the LED tube lamp, but rather some components of theinstallation detection module can be integrated into an integratedcircuit in an exemplary embodiment (e.g., the embodiment illustrated inFIG. 17A). Alternatively, all circuit components of the installationdetection module can be integrated into an integrated circuit in anotherexemplary embodiment (e.g., the embodiment illustrated in FIG. 18A).Therefore, the circuit cost and the size of the installation detectionmodule can be saved. In addition, by integrating/modularizing theinstallation detection module, the installation detection module can bemore easily utilized in different types of the LED tube lamps so thatthe design compatibility of the LED tube lamp can be improved. Also,under the application of utilizing the integrated installation detectionmodule in the LED tube lamp, the light emitting area of the LED tubelamp can be significantly improved since the circuit size within thetube lamp is reduced. For example, the integrated circuit design mayreduce the working current (reduced by about 50%) and enhance the powerefficiency of the integrated components. As a result, the saved powercan be used for being supplied to the LED module for emitting light, sothat the luminous efficiency of the LED tube lamp can be furtherimproved.

To summarize, the embodiments illustrated in FIG. 13A to FIG. 44C teacha concept of electric shock protection by utilizing electrical controland detection method. Compared to mechanical electric shock protection(i.e., using the mechanical structure interaction/shifting forimplementing the electric shock protection), the electrical electricshock protection has higher reliability and durability since themechanical fatigue issue may not occur in the electrical installationdetection module.

It should be noted that in embodiments of using detection pulse(s) forinstallation detection, the installation detection module in operationdoes not or will not substantially change characteristics and states ofthe LED tube lamp having the installation detection module that arerelated to LED driving and light emitting by the LEDs. Thecharacteristics related to LED driving and light emitting by the LEDsinclude for example characteristics, such as phase of the power linesignal and output current for the LED module, which can affect thebrightness of light emission and output power of the lighted-up LED tubelamp. Operations of the installation detection module are only concernedwith or related to leakage current protection when the LED tube lamp isnot yet lighted up, which purpose makes the installation detectionmodule distinctive from circuits used to adjust characteristics of LEDlighting states, such as a DC power conversion circuit, a power factorcorrection circuit, and a dimmer circuit.

FIG. 42A is a block diagram of a power supply module in an LED tube lampaccording to some embodiments. Compared to the above describedembodiments, the power supply module in this embodiment of FIG. 42Aincludes a rectifying circuit 510, a filtering circuit 520, and adriving circuit 530, and further includes a misuse warning module 580.The misuse warning module 580 is coupled to the rectifying circuit 510;is configured to detect the power line voltage and judge according tothe detection result whether an input external driving signal is an ACsignal provided by an electronic ballast; and is configured to controlthe operation or lighting mode of the LED tube lamp according to thejudging result. By this way of operating the misuse warning module 580,when a ballast-bypass LED tube lamp is installed by mistake to a lampsocket of a ballast, the ballast-bypass LED tube lamp then issues awarning (as in the form of flashing) to alert or remind a user of themisuse situation, for preventing an AC signal output by an electronicballast from damaging the ballast-bypass LED tube lamp.

An exemplary configuration of a misuse warning module 580 is illustratedin FIG. 42B. FIG. 42B is a block diagram of a misuse warning moduleaccording to some embodiments. In this embodiment of FIG. 42B, themisuse warning module 580 includes a misuse detection control circuit583 and a switching circuit 584. The misuse detection control circuit583 is configured to detect the power line voltage and to judgeaccording to a signal feature of the detected power line voltage whetheran input external driving signal currently received by the LED tube lampof the misuse warning module 580 is an AC signal output by an electronicballast or directly provided by a commercial power grid. Since an ACsignal output by a ballast (especially an electronic ballast) hascharacteristics of having relatively high frequency and/or high voltage,but an AC signal output by a power grid typically has characteristics ofhaving relatively low frequency (such as in the range of 50 Hz to 60 Hz)and/or low voltage (generally lower than 305V), the source of anexternal driving signal input to the LED tube lamp can be identified bydetecting a signal feature, such as the frequency, amplitude, or phase,of the power line voltage signal input in a power supply module of theLED tube lamp.

In some embodiments, when the misuse detection control circuit 583detects a signal feature of the power line voltage as conforming to thatof a type of output signal provided by a commercial power grid, thisindicates that the currently input external driving signal is or mightbe an AC signal provided by an AC power grid, then the misuse detectioncontrol circuit 583 issues a control signal to conduct the switchingcircuit 584, thereby maintaining a power loop in the LED tube lamp in aconducting state. On the other hand, when the misuse detection controlcircuit 583 detects a signal feature of the power line voltage as notconforming to that of a type of output signal provided by a commercialpower grid, this indicates that the currently input external drivingsignal is or might be an AC signal provided by an electronic ballast,then the misuse detection control circuit 583 issues a control signal tocontrol switching of the switching circuit 584, in order to affect thecontinuity of current in a power loop of the LED tube lamp and cause alater-stage LED module to generate or emit a specific light pattern as amisuse warning, in response to variation in the continuity of a currentflowing in the power loop.

In some embodiments, upon controlling the switching circuit 584 so as toissue a misuse warning, the misuse detection control circuit 583maintains the switching circuit 584 in a cutoff state, thereby avoidingthe potential danger to a user due to not immediately removing the LEDtube lamp from the incompatible lamp socket.

FIG. 43 is a block diagram of a power supply module in an LED tube lampaccording to some embodiments. The power supply module in thisembodiment of FIG. 43 includes a rectifying circuit 510, a filteringcircuit 520, and a driving circuit 530, and further includes a misusewarning module 680. The misuse warning module 680 is configured todetect the power line voltage and judge according to the detectionresult whether an input external driving signal is an AC signal providedby an electronic ballast; and is configured to according to thedetermination result issue a misuse warning (such as a sounding) toalert or remind a user of a misuse situation, in order to prevent an ACsignal output by an electronic ballast from damaging a ballast-bypassLED tube lamp. Compared to the embodiments of FIG. 42A, since the misusewarning module 680 is not designed to control an LED module to show alight pattern as a misuse warning, it is not needed to serially connectthe misuse warning module 680 on the power loop of the LED tube lamp.

In this embodiment of FIG. 43, the misuse warning module 680 includes amisuse detection control circuit 683 and a warning circuit 684. Themisuse detection control circuit 683 is configured to detect the powerline voltage and to judge according to a signal feature of the detectedpower line voltage whether an input external driving signal currentlyreceived by the LED tube lamp of the misuse warning module 680 is an ACsignal output by an electronic ballast or directly provided by acommercial power grid.

In some embodiments, when the misuse detection control circuit 683 ofFIG. 43 detects a signal feature of the power line voltage as conformingto that of a type of output signal provided by a commercial power grid,this indicates that the currently input external driving signal is ormight be an AC signal provided by an AC power grid, then the misusedetection control circuit 683 disables the warning circuit 684, causingthe warning circuit 684 not to issue a misuse warning. On the otherhand, when the misuse detection control circuit 683 detects a signalfeature of the power line voltage as not conforming to that of a type ofoutput signal provided by a commercial power grid, this indicates thatthe currently input external driving signal is or might be an AC signalprovided by an electronic ballast, then the misuse detection controlcircuit 683 enables the warning circuit 684, causing the warning circuit684 to issue a misuse warning. In some embodiments, the warning circuit684 comprises or is embodied by a buzzer, in order to buzz to alert theuser of the misuse situation when the ballast-bypass LED tube lamp isinstalled by mistake to a lamp socket of a ballast.

Concrete operation mechanism(s) of an LED tube lamp having a misusewarning module are further explained with reference to FIG. 44D. FIG.44D is flowchart of steps of a method to control a misuse warning moduleaccording to some embodiments. Referring to FIG. 44D, upon a powersupply module of an LED tube lamp receiving an external driving signal,a misuse warning module of the LED tube lamp detects a signal on a powerloop of the LED tube lamp (step S401) and then judges whether a detectedsignal feature conforms to a first signal feature (step S402). The firstsignal feature may be one of the electrical signal characteristics suchas frequency, amplitude, and phase. In the embodiment of FIG. 44D, thefirst signal feature for example conforms to that of an output signal ofan AC power grid, but the present invention is not limited to this case.In some embodiments, the first signal feature is set conforming to thatof an output signal of an electronic ballast.

Still referring to FIG. 44D, proceeding further in the method ofcontrolling a misuse warning module, when the misuse warning modulejudges that the detected signal feature or characteristic conforms tothe first signal feature, this indicates that the currently inputexternal driving signal is or might be an AC signal provided by an ACpower grid, so the misuse warning module does not issue a misuse warning(step S403), and according to a set operation sequence related to misusedetection in the power supply process causes the LED tube lamp tonormally light up (i.e. entering into or maintaining in a normaloperation mode) or causes an installation detection module to performinstallation detection (in a detection mode). On the contrary, when themisuse warning module judges that the detected signal feature does notconform to the first signal feature, this indicates that the currentlyinput external driving signal is or might be an AC signal provided by anelectronic ballast, so the misuse warning module issues a misuse warning(step S404). In some embodiments, upon issuing a misuse warning, themisuse warning module further causes the LED tube lamp to enter into arestriction mode (step S405). Under the restriction mode, the misusewarning module may prohibit the LED tube lamp from lighting up (i.e. adriving current is prevented from passing or being generated), orrestrict or limit the LED tube lamp to operating in a limited-currentstate (i.e. the magnitude of a driving current is lowered or limited),in order to prevent the LED tube lamp from being damaged. So such arestriction mode of an LED tube lamp may ensure the LED tube lamp safelyoperates, by limiting an output power of the power supply module of theLED tube lamp to being below its power rating.

It's noted that depending on design needs, the first signal feature as adetermination basis may be designed to conform to a signal feature of anoutput signal of an AC power grid or of an electronic ballast, so if itis an electronic ballast, the possible determination results at the stepS402 in FIG. 44D can be logically exchanged and then correspond to thefollowing two steps S403 and S404 respectively. These two alternativesmay be considered equivalents within the context of FIG. 44D. Forexample, if the first signal feature is chosen as conforming to that ofan output signal of an electronic ballast, the determination results atthe step S402 in FIG. 44D are exchanged such that the step S403 isperformed if the determination result is negative (meaning theballast-bypass LED tube lamp is likely not installed by mistake to alamp socket of a ballast) and the steps S404 and S405 are performed ifthe determination result is positive. However, the present invention isnot limited to this case.

In some embodiments of using an installation detection module togetherwith a misuse warning module, such as using the installation detectionmodule 3000 a including a ballast detection module 3400 of FIG. 15A, thesteps of misuse detection may be performed in a detection mode of an LEDtube lamp. For example, operations for misuse detection by a misusewarning module (or ballast detection module) and operations forinstallation detection by an installation detection module may beperformed concurrently or in proper order, and when a misuse situationis detected by the misuse warning module a misuse warning is issued andthe LED tube lamp is then caused to enter into a restriction mode. Insome other embodiments, the steps of misuse detection may be performedin a normal operation mode of an LED tube lamp. For example, uponjudging that the LED tube lamp has been correctly installed to a lampsocket an installation detection module is configured to cause the LEDtube lamp to enter into a normal operation mode to enable normallighting of the LED tube lamp. Under the normal operation mode, a misusewarning module (or ballast detection module) is configured to performoperations for misuse detection, and when a misuse situation is detecteda misuse warning is issued and the LED tube lamp is then caused to leavethe normal operation mode to enter into a restriction mode.

It's also noted that although the described optional emergency controlmodule (such as 3140, 3240, and 4140), ballast detection module (such as3150 and 4150), warning circuit (such as 3160), and dimming circuit 5170are each described or explained above with reference to some directlyrelevant embodiments, a person of ordinary skill in the art afterreading the description herein can readily and clearly understandapplicable configurations and operations of such optional modules and/orcircuits when applied in other embodiments of an installation detectionmodule which are different from such optional modules' respective abovedescribed embodiments, for example when applied in the embodiments ofinstallation detection modules 2000-8000, or especially when applied inthe embodiments of installation detection modules 3000 a-3000L, 4000 a,5000 a, and 6000 a.

In some embodiments, the power supply module can be divided into twosub-modules, in which the two sub-modules are respectively disposed inthe different end caps and the sum of power of the sub-modules equals tothe predetermined output power of the power supply module.

According to some embodiments, the present invention further provides adetection method adopted by a light-emitting device (LED) tube lamp forpreventing a user from electric shock when the LED tube lamp is beinginstalled in a lamp socket. The detection method includes: generating afirst pulse signal by a detection pulse generating module, wherein thedetection pulse generating module is configured in the LED tube lamp;receiving the first pulse signal through a detection result latchingcircuit by a switch circuit, and making the switch circuit conductingduring the first pulse signal to cause a power loop of the LED tube lampto be conducting, wherein the switch circuit is on the power loop; anddetecting a first sample signal on the power loop by a detectiondetermining circuit as the power loop being conductive, and comparingthe first sample signal with a predefined signal, wherein when the firstsample signal is greater than or equal to the predefined signal, thedetection method further includes: outputting a first high level signalby the detection determining circuit; receiving the first high levelsignal by the detection result latching circuit and outputting a secondhigh level signal; and receiving the second high level signal by theswitch circuit and conducting to cause the power loop to remainconductive.

In some embodiments, when the first sample signal is smaller than thepredefined signal, the detection method further includes: outputting afirst low level signal by the detection determining circuit; receivingthe first low level signal by the detection result latching circuit andoutputting a second low level signal; and receiving the second low levelsignal by the switch circuit and maintaining an off state of the switchcircuit to cause the power loop to remain open.

In some embodiments, when the power loop remains open, the detectionmethod further includes: generating a second pulse signal by thedetection pulse generating module; receiving the second pulse signalthrough the detection result latching circuit by the switch circuit, andchanging an off state of the switch circuit to a conducting state againduring the second pulse signal to cause the power loop to be conductingonce more; and detecting a second sample signal on the power loop by thedetection determining circuit as the power loop being conductive oncemore, and comparing the second sample signal with the predefined signal,wherein when the second sample signal is greater than or equal to thepredefined signal, the detection method further includes: outputting thefirst high level signal by the detection determining circuit; receivingthe first high level signal by the detection result latching circuit andoutputting the second high level signal; and receiving the second highlevel signal by the switch circuit and maintaining a conducting state ofthe switch circuit to cause the power loop to remain conducting.

In some embodiments, when the second sample signal is smaller than thepredefined signal, the detection method further includes: outputting thefirst low level signal by the detection determining circuit; receivingthe first low level signal by the detection result latching circuit andoutputting the second low level signal; and receiving the second lowlevel signal by the switch circuit and maintaining an off state of theswitch circuit to cause the power loop to remain open.

In some embodiments, a period (or a width) of the first pulse signal isbetween 10 microseconds-1 millisecond, a period (or a width) of thesecond pulse signal is between 10 microseconds-1 millisecond.

In some embodiments, a time interval between the first and the secondpulse signals (or a cycle of the pulse signal) includes (X+Y)(T/2),where T is the cycle of the external driving signal, X is an integerwhich is bigger than or equal to zero, 0<Y<1.

In some embodiments, a period (or a width) of the first pulse signal isbetween 1 microsecond-100 microseconds, a period (or a width) of thesecond pulse signal is between 1 microsecond-100 microseconds.

In some embodiments, a time interval between the first and the secondpulse signals (or a cycle of the pulse signal) is between 3milliseconds-500 milliseconds.

In some embodiments, a protection device is electrically connectedbetween the power supply module and the pins on the end caps. Forexample, a rated current fuse or a resistance type fuse (e.g., picofuse) may be used.

In some embodiments, at least two protection elements, such as twofuses, are respectively connected between the internal circuits of theLED tube lamp and the conductive pins of the LED tube lamp, and whichare on the power loop of the LED tube lamp. In some embodiments, fourfuses are used for an LED tube lamp having power-supplied at its bothend caps respectively having two conductive pins. In this case, forexample, two fuses are respectively connected between two conductivepins of one end cap and between one of the two conductive pins of thisend cap and the internal circuits of the LED tube lamp; and the othertwo fuses are respectively connected between two conductive pins of theother end cap and between one of the two conductive pins of the otherend cap and the internal circuits of the LED tube lamp. In someembodiment, the capacitance between a power supply (or an externaldriving source) and the rectifying circuit of the LED tube lamp may beranging from 0 to about 100 pF. In some embodiments, the abovementionedinstallation detection module may be configured to use an external powersupply.

According to the design of the power supply module, the external drivingsignal may be a low frequency AC signal (e.g., commercial power) or a DCsignal (e.g., that provided by a battery or external configured drivingsource), input into the LED tube lamp through a drive architecture ofdual-end power supply. For the drive architecture of dual-end powersupply, the external driving signal may be input by using only one endthereof as single-end power supply.

The LED tube lamp may omit the rectifying circuit in the power supplymodule when the external driving signal is a DC signal.

According to the design of the rectifying circuit in the power supplymodule, there may be a dual rectifying circuit. First and secondrectifying circuits of the dual rectifying circuit are respectivelycoupled to the two end caps disposed on two ends of the LED tube lamp.The dual rectifying circuit is applicable to the drive architecture ofdual-end power supply. Furthermore, the LED tube lamp having at leastone rectifying circuit is applicable to the drive architecture of a lowfrequency AC signal, high frequency AC signal or DC signal.

The dual rectifying circuit may comprise, for example, two half-waverectifier circuits, two full-wave bridge rectifying circuits or onehalf-wave rectifier circuit and one full-wave bridge rectifying circuit.

According to the design of the pin in the LED tube lamp, there may betwo pins in single end (the other end has no pin), two pins incorresponding ends of two ends, or four pins in corresponding ends oftwo ends. The designs of two pins in single end and two pins incorresponding ends of two ends are applicable to a single rectifyingcircuit design of the rectifying circuit. The design of four pins incorresponding ends of two ends is applicable to a dual rectifyingcircuit design of the rectifying circuit, and the external drivingsignal can be received by two pins in only one end or any pin in each oftwo ends.

According to the design of the filtering circuit of the power supplymodule, there may be a single capacitor, or π filter circuit. Thefiltering circuit filters the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI resulted from the circuit(s) of theLED tube lamp. The LED tube lamp may omit the filtering circuit in thepower supply module when the external driving signal is a DC signal.

The LED module may be electrically connected with a voltagestabilization circuit in parallel for preventing the LED module fromover voltage. The voltage stabilization circuit may be a voltageclamping circuit, such as Zener diode, DIAC and so on. When therectifying circuit has a capacitive circuit, in some embodiments, twocapacitors are respectively coupled between two corresponding pins intwo end caps and so the two capacitors and the capacitive circuit as avoltage stabilization circuit perform a capacitive voltage divider.

If the external driving signal is a high frequency AC signal, acapacitive circuit (e.g., having at least one capacitor) is in at leastone rectifying circuit and the capacitive circuit is electricallyconnected in series with a half-wave rectifier circuit or a full-wavebridge rectifying circuit of the rectifying circuit and serves as acurrent modulation circuit (or a current regulator) to modulate or toregulate the current of the LED module due to that the capacitor equatesa resistor for a high frequency signal. In addition, an energy-releasingcircuit is electrically connected in parallel with the LED module. Whenthe external driving signal is no longer supplied, the energy-releasingcircuit releases the energy stored in the filtering circuit to lower aresonance effect of the filtering circuit and other circuits forrestraining the flicker of the LED module. In some embodiments, thedriving circuit may be a buck converter, a boost converter, or abuck-boost converter. The driving circuit stabilizes the current of theLED module at a defined current value, and the defined current value maybe modulated based on the external driving signal. For example, thedefined current value may be increased with the increasing of the logiclevel of the external driving signal and reduced with the reducing ofthe logic level of the external driving signal. Moreover, a modeswitching circuit may be added between the LED module and the drivingcircuit for switching the current from the filtering circuit directly orthrough the driving circuit inputting into the LED module.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to the design of the auxiliary power module of the powersupply module, the energy storage unit may be a battery (e.g., lithiumbattery, graphene battery) or a supercapacitor, electrically connectedin parallel with the LED module.

According to the design of the LED module of the power supply module,the LED module comprises plural strings of LEDs electrically connectedin parallel with each other, wherein each LED may have a single LED chipor plural LED chips emitting different spectrums. Each LEDs in differentLED strings may be electrically connected with each other to form a meshconnection.

The above-mentioned exemplary features of the present invention can beaccomplished in any combination to improve the LED tube lamp, and theabove embodiments are described by way of example only. The presentinvention is not herein limited, and many variations are possiblewithout departing from the spirit of the present invention and the scopeas defined in the appended claims.

What is claimed is:
 1. A circuit board configuration adapted to carryelectronic components of a power supply module, wherein the power supplymodule is disposed in an LED tube lamp having a lamp tube and two endcaps connected to respective ends of the lamp tube, and the circuitboard configuration comprises: a first circuit board, having a firstplane configured on which to dispose and connect a part of theelectronic components; and a second circuit board, electricallyconnected to the first circuit board and having a second planeconfigured on which to dispose and connect another part of theelectronic components, wherein at least one of the first and the secondcircuit boards is disposed, perpendicular to an axial direction of thelamp tube, in an interior space formed by the lamp tube and in at leastone of the two end caps, so that a first direction normal to the firstand the second planes is substantially parallel to the axial directionof the lamp tube.
 2. The circuit board configuration according to claim1, wherein at least one of the first and the second circuit boards isarranged toward to an end wall of the at least one of the end caps,along the axial direction.
 3. The circuit board configuration accordingto claim 1, wherein the first and the second circuit boards are bondedtogether by wires.
 4. The circuit board configuration according to claim1, wherein at least one of the first and the second circuit boards is adisk-shaped circuit board having a disk-shaped structure.
 5. The circuitboard configuration according to claim 4, wherein a maximum outerdiameter of the disk-shaped circuit board is smaller than an innerdiameter of the corresponding end cap.
 6. The circuit boardconfiguration according to claim 1, wherein the part of the electroniccomponents disposed on the first circuit board comprises: an impedancedetection controller, configured to perform, before the LED tube lamp islighted up, an impedance detection to determine whether the LED tubelamp is electrically connected to a foreign external impedance inseries.
 7. The circuit board configuration according to claim 6, whereinthe impedance detection controller causes at least one transientvariation to an operating current of the LED tube lamp for detecting anequivalent impedance and limits the operating current of the LED tubelamp to not exceed 5 MIU in root-mean-square (RMS) when the LED tubelamp is electrically connected to the foreign external impedance inseries.
 8. The circuit board configuration according to claim 7, whereina duration of each transient variation does not exceed 1 millisecondwhen the impedance detection controller performs the impedancedetection.
 9. The circuit board configuration according to claim 7,wherein the impedance detection controller causes at least two transientvariations within a first detection period when the LED tube lamp iselectrically connected to the foreign external impedance in series, aduration of each transient variation does not exceed 1 millisecond, andthe time difference between adjacent transient variations is in a rangeof between plus and minus 15% of 75 milliseconds.
 10. The circuit boardconfiguration according to claim 9, wherein the impedance detectioncontroller causes, after the first detection period, at least twotransient variations within a second detection period, and wherein thereis a time interval between the first detection period and the seconddetection period.
 11. The circuit board configuration according to claim10, wherein the time interval is in a range of 0.5 seconds to 2 seconds.12. The circuit board configuration according to claim 7, wherein theimpedance detection controller is activated to perform the impedancedetection when the LED tube lamp receives an external driving signal,and triggers the transient variation during a falling time of theexternal driving signal.
 13. The circuit board configuration accordingto claim 12, wherein the impedance detection controller triggers thetransient variation when the external driving signal reaches a firstvoltage level or a first phase during the falling time.
 14. The circuitboard configuration according to claim 7, wherein the impedancedetection controller is activated to perform the impedance detectionwhen the LED tube lamp receives an external driving signal, and triggersthe transient variation during a rising time of the external drivingsignal.
 15. The circuit board configuration according to claim 14,wherein the impedance detection controller triggers the transientvariation when the external driving signal reaches a first voltage levelor a first phase during the rising time.
 16. The circuit boardconfiguration according to claim 6, wherein the other part of theelectronic components is disposed on the second circuit board andcomprises: a rectifying circuit, configured to rectify an externaldriving signal received by the LED tube lamp; and a filtering circuit,configured to filter a signal received from the rectifying circuit,wherein the impedance detection controller has a first terminalelectrically connected to an output of the rectifying circuit and asecond terminal electrically connected to an input of the filteringcircuit.
 17. The circuit board configuration according to claim 16,wherein the other part of the electronic components disposed on thesecond circuit board further comprises: a driving circuit, configured togenerate a driving current for driving an LED module of the LED tubelamp, wherein the driving circuit is electrically connected to thesecond terminal of the impedance detection controller via the filteringcircuit.
 18. The circuit board configuration according to claim 16,wherein the impedance detection controller is configured to receive afirst signal reflecting a voltage level of the output of the rectifyingcircuit by a third terminal.
 19. The circuit board configurationaccording to claim 16, wherein the impedance detection controller isconfigured to receive a first signal reflecting a voltage level of theexternal driving signal by a third terminal.
 20. The circuit boardconfiguration according to claim 19, wherein the other part of theelectronic components disposed on the second circuit board furthercomprises: a first diode, having an anode electrically connected to afirst input of the rectifying circuit, and a cathode electricallyconnected to the third terminal of the impedance detection controller;and a second diode, having an anode electrically connected to a secondinput of the rectifying circuit, and a cathode electrically connected tothe cathode of the first diode.
 21. The circuit board configurationaccording to claim 6, wherein the other part of the electroniccomponents is disposed on the second circuit board and comprises: aballast detection circuit, electrically connected to the impedancedetection controller, and configured to detect a signal feature of anexternal driving signal received by the LED tube lamp and determinewhether the external driving signal is provided by an electronic ballastor directly by a power grid.
 22. The circuit board configurationaccording to claim 21, wherein when the external driving signal isprovided by an electronic ballast, the ballast detection circuitbypasses at least one component of the impedance detection controller toblock the impedance detection.
 23. The circuit board configurationaccording to claim 1, wherein the first circuit board has a male plugand the second circuit board has a female plug configured to connect tothe male plug.